I think a big challenge is that often different interventions appear better or worse depending on the time horizon. That's apparent in this case: if corporate campaigns get a dozen companies to commit to buying cage-free eggs, that will have benefits in a matter of years. It's not clear what the long-term impacts will be (maybe a changing corporate culture that becomes more conscious of animal welfare? Maybe higher prices, leading to lower consumption of animal products?) but the theory of change isn't normally spelled out over that time  horizon. For alternative proteins, the short-term benefits are rather modest, and the much more important benefits seem long-term, if it can lead to a much bigger plant-based market, there's a high chance that people will be more willing to consider changing their diet (and their ethics) completely. 

I would really like to see more long-term theories of change within animal advocacy. I even find it a bit odd that it isn't more normal, given the buzz around longtermism within EA.

I also find this a very exciting question and would like to read more about it. I am also surprised that there has been relatively little written about it so far. I would assume that ACE must have made some comparisons in past years, back when GFI was still being evaluated.

A few remarks:

• For charities in the alt-protein space, it definitely makes sense to also seek funding from the climate sector, because there is simply more money available there overall than in the animal welfare sector. If a charity like GFI ranks among the most cost-effective charities in two areas, it could even make sense for both donors with a climate background and donors with an animal background to agree on donating to GFI. See this interesting article on the EA Forum.
• For strategic reasons, GFI has never put the topic of animal welfare front and center. As far as I know, GFI no longer being evaluated by ACE also has other reasons, namely that GFI has become very large, and with that the effort required for an evaluation, relative to the expected benefit (especially ACE's recommended charities fund), has become very high.
• From my perspective, the comparison between donations to THL and investing in an alt-protein startup is somewhat off, because an investment is about getting the money back, ideally with a return, whereas a donation is not. Accordingly, I would assume that a donation to, for example, GFI has more impact than an investment of the same amount in a startup. If that were not the case, all GFI donors should invest in startups instead. I find this assumption plausible, because GFI can do things that benefit the entire ecosystem, for example advocating for public research funding.
• By the way, GFI does not receive government funding, and I think this is also not planned.
• Social norms are definitely a factor in the adoption of cultivated meat. However, I believe that social norms can also change, and will change, especially if the alternatives are cheaper and tastier. In that sense, I would not put too much weight on statements by people today who say they will never switch, even if it were cheaper and tastier. That may be true in individual cases, but I see no reason why the younger generation should opt for slaughter-based meat if it is more expensive and less tasty.

Some rough ideas on how one might model the overall calculation: One option would be to assign each change, for example higher animal welfare standards or higher consumption of alternative products, a durability or half-life. That is, without additional follow-up intervention, the effect of an intervention persists for X years or is reduced by half within X years. Another option would be to assume a long-term baseline trajectory, for example how the share of people living vegan develops over time or how animal welfare legislation evolves over time, and then, for each intervention, try to measure how much it brings a given stage of development forward in time. For example, reaching 2 percent of people living vegan five years earlier than assumed, whereas in the baseline scenario the share in those five years would have been 1 percent. An important question in this context would be whether reaching a development stage earlier also shifts later states forward in time, for example when 50 percent of people live vegan.

I think corporate outreach has had, and will likely continue to have, a wider impact on animal welfare than getting rid of battery cages although that's certainly one of the bigger wins. As to your second point, I think you're right that this parameter depends on culture and regulation; although I want to be optimistic, it might be somewhat overly optimistic to think that alternative proteins will ever capture 100% of the market. This also ties into your fourth point on the barriers to shifting to alternative proteins. I'd have to look for the research on this but I'm confident that many people, today at least, would say that they'll never switch in the future, even if taste and cost were the same (maybe down to tradition, fear of UPFs etc). So social norms will likely play a big role here, and shifting social norms can never be guaranteed - certainly not within a short time frame.

Corporate outreach almost guarantees small wins (when compared with ending, or almost ending, animal farming) today, so investment is low-risk. The chance of this kind of advocacy hugely reducing the number of farmed animals overall though seems almost negligible. Alternative proteins, if everything goes well, could result in a much bigger win, but the risk seems pretty high at the moment - it must be higher than many people are comfortable with.

Hi Pablo! I wanted to offer two thoughts that are admittedly not answers to your questions, but complicate how I think about questions like this. 

1. I don't typically think of questions like this as either/or questions, but "to what degree" questions. A movement that successfully eliminates animal suffering, ends factory farming, or however you might frame the goal of organizations like THL and GFI will likely require both approaches. The question then is to what degree should each intervention be funded to create an optimal movement ecosystem. 

2. One consideration that I wanted to offer, which may not fit neatly into a model like what you're looking for, is the role of philanthropy as a funding source for that intervention type. From what I understand, an organization like GFI is able to attract non-philanthropic sources of funding, like venture capital and perhaps government funding, as you suggest. An advocacy organization like THL, due to its adversarial role, is not. This increases the importance of philanthropic funding for an organization like THL. 

Re alternative proteins - as well as cultivated meat, there is precision fermentation. This could be used to produce a lot of the dairy and egg proteins that are used in food manufacturing, and would be less dependent on consumer acceptance. Precision fermentation also seems to be less technically challenging than cultured meat. 

Don’t have answers but just wanted to say I really appreciate this mini-compilation of what’s already been done 

Some thoughts:

1. Abolishment vs welfarism. The goals of the movement may diverge in both the long term vision (complete abolishment vs happy farms) and in respect to the medium term (less animals grown for food vs animals grown for food have better living standards).
2. Difference between species and tradeoffs between them (e.g. increased cost of pig meat can increase consumption of chicken meat).
3. As others have noted, there are important secondary effects on the movement itself for most interventions. I think it is a very important meta- question about how prioritization should account for it.