I didn't mean to cite the Korea study as an example of plant-based campaigns. It is not. It's a nationalist and traditionalist campaign but it shows that diet change campaigns such as cooking courses have been (cited as) highly effective; at least the study claims that the government campaigns were a main contributor to the fact that Korea is the least obese country in the OECD.
One would also need to change school curricula with their food pyramid, direct change in public catering, get nutritionists to agree that animal protein has no benefits etc. Most animal/vegan organisations are working on that in some way but aren't hugely successful (vegans are only 1% in most societies) - it is hard to work on the demand side. But if you take away the supply then it might be easier. People choose food mostly because of taste, price and convenience, not much because it contains an animal product.
So if animal products are restricted due to pandemic risk, they're more expensive and market forces will drive them out.
You're right about replacing livelihoods, buyouts / nationalisation programs and reactance from 'luddite' farmers. I think this is actually a more difficult point than changing diets, and something the animal people are ignoring a bit. Interesting with the $10 bn US buyout in 2004. It doesn't seem that much, it's about 0.43% of the federal budget (which was $2.3trn and 19% of GDP in 2004), but the cost might be higher for an animal husbandry buyout.
Anyone, please let me know if you're interested in working on this or have more information:
It seems important to more accurately estimate the economic cost of different pandemic mitigation options, including my 'species distancing'. There are emotional costs, too; economic arguments against Brexit haven't convinced everyone. These apply both to fears of dying from zoonotic disease and fears of having to eat a vegan steak and having to replace one's livelihood. Again, these would be good to quantify. There are also distributional costs; Julia_Wise mentions low-income people who hunt for a living (perhaps even illegally, see bans on pangolin hunts and its role in covid-19, or illegal use of great apes and the potential origin of the HIV virus).
 https://www.cam.ac.uk/vegnudge https://europepmc.org/article/pmc/pmc6800350
// On tractability and implementation
Thanks for your thoughts! I agree with everything you say but one thing, but maybe you can explain a bit more so I understand: "Even if governments decided they wanted to do this, it's a much harder step to take than a lot of other steps they could take toward reducing pandemic risk"
Are you referring to specific measures? One much-proposed idea seems to invest in medical systems. However, that costs around 3% of world GDP whereas my measures don't seem to cost much. Readying healthcare systems to nip pandemics in the bud also seems very unlikely to be solved in the next decades in developing and emerging economies, where most pandemics originate.
The developing country origin of pandemics means that my measures might be the next best option if healthcare is too expensive, but it also means that they must be implemented in developing countries if they are to be successful.
My intuition is that any solution will be driven by superpowers such as the US and China, which are able to partially coerce the others. I also suspect that global sentiment towards development assistance is currently so bad that it is easier to convince superpowers to force a meat and game reduction from poor countries than it is to convince superpowers to fund poor countries' healthcare systems. Some states may resist (such as Tadjikistan), but that's a problem for any measure to prevent pandemics.
Another problem is shadow markets. They persist for many products and services that governments have tried to discourage, like drugs and prostitution. However, unlike with those two, there is a clear, safe and cheap substitute for animal products - plant products.
Governments around the world seem quite successful in shutting down entire sectors of their economies right now. Why not animal farming and hunting? Governments have successfully influenced diets systems in the past. They promoted crops from other continents such as potatoes and maize. South Korea promoted a particular form of traditional cuisine with public cooking courses.
We only need to convince governments, i.e. we need a stronger medical case.
 "The most cost-effective strategies for increasing pandemic preparedness, especially in resource-constrained settings, consist of investing to strengthen core public health infrastructure, including water and sanitation systems; increasing situational awareness; and rapidly extinguishing sparks that could lead to pandemics." https://www.ncbi.nlm.nih.gov/books/NBK525302/
 https://data.worldbank.org/indicator/SH.XPD.CHEX.GD.ZS hows how much is spent on healthcare by government and private individuals. If you compare developed to developing economies, there are gaps of 5-7% of GDP between rich and poor countries (e.g. the Euro area spends 10% of GDP and Sub-Saharan Africa spend 5%). We would have to spend maybe 3% of world GDP if we were to make all public health systems industrial standard. This takes into account that the share of not-pandemic-ready countries is maybe 60% but that it is cheaper to make these countries ready because labour costs are lower. However, it does not account for the cost of building working education systems for doctors and nurses.
 This seems partly due to the correlation of developing country status and tropical areas, which in turn correlate with high biomass and therefore many zoonoses (I heard in a news report on German state TV which is usually reliable). It's probably also because developing countries are just so resource-constrained that they're bad at nipping pandemics in the bud (would SARS-Cov-2 be a thing had it emerged from bats in Canada?).
 Behavioural Insights Team, 2020. Menu for Change, pp.19-21. https://www.bi.team/wp-content/uploads/2020/03/BIT_Report_A-Menu-for-Change_Webversion_2020.pdf.pdf
 Soowon Kim, Soojae Moon, Barry M Popkin, The nutrition transition in South Korea, The American Journal of Clinical Nutrition, Volume 71, Issue 1, January 2000, Pages 44–53, https://doi.org/10.1093/ajcn/71.1.44
"A more plausible explanation is that movements to retain the traditional diet have been strong in South Korea. These movements include mass media campaigns, such as television programs that promote local foods by emphasizing their higher quality and the need to support local farmers (eg, Korean Broadcasting System First station's daily program Six O'clock My Village introduces famous products of South Korean villages and promotes consumption of traditional dishes). South Korea also promoted the concept of “Sin-To-Bul-Yi” (translated directly as “A body and a land are not 2 different things,” meaning that a person should eat foods produced in the land in which he or she was born and is living).
Part of this effort is reflected in a unique training program offered by South Korea's Rural Development Administration. Beginning in the 1980s, the Home Management Division of the Rural Living Science Institute trained thousands of extension workers to provide monthly training sessions on cooking methods of traditional Korean foods such as rice, kimchi (pickled and fermented Chinese cabbage), and fermented soybean foods. These sessions are open to the public in most districts of the country and the program appears to reach a large audience (41)"