I think this is a good question. To me, EA is pretty ruthless in how it assesses effectiveness, and that leads to many causes feeling left out (especially when those causes are close to you personally).
Taken to an extreme, if all charitable acts/giving was done through an EA lens, it would feel pretty brutalist to any cause not included in its scope. Though from an EA lens, this would be a *more effective* charitable sector and ultimately reduce suffering/increase overall wellbeing.
But the simple reality is EA is small relative to the universe of charitable acts. And I think having a portion of charitable acts approached with an EA lens is a good thing. And I think the actual % is significantly lower than the optimal %.
Type 1 diabetic and long time EA here.
Generally when I have donated to help people directly (most of my recent donations have not been of this form, to be clear, in recent years my donations have been focused on research or on helping animals) I am not really thinking about how big the problem is. I am thinking "what will the consequence of this donation be?" If I am donating less than millions of dollars, I'm not likely to solve the whole issue, so the question of if the issue is big or small in a global sense just isn't very important.
For type 1 diabetes, what can a donation of $5k do? I'm not sure, but the baseline for what I can do with $5k in the global health space is "prevent a child from dying of malaria", so I would want to find something I thought was better than that before doing so.
That last bit is the key to the EA mindset to me - given a fixed donation budget, every time we choose to give to something, we are choosing not to give that money to everything else. So we ought to triage, and give to where we think the money or effort can do the most good.
For someone who knows of a really high leverage way to impact the affordability or availability of insulin (or for a researcher with a chance of discovering a cure or improved treatment), it might be that the best place for them to focus their efforts is on that. There are millions of type 1 diabetics, so any one person who could make a meaningful impact there could have enormous impact. But it's still good for them to ask the question and be aware of what other avenue to impact they might have, if their goal is to do the most good.
Great answer, thank you!