> When you say "Iterate until/unless new data comes along suggesting otherwise", does that mean you will want to continue adding more friction and more restrictions as long as a number or percentage of people (that exceeds some threshold) continue to get scammed?

All it means is "keep reevaluating the situation and your approach based on the data." I can't possibly claim to have all the answers for every hypothetical available right here.

> It seems to me that you have a mental model where some small, reasonable changes will dramatically reduce the number of scam victims to near zero.

Replace "will...near zero" with "has a reasonable chance of...low enough that the fish becomes too small to fry" and you might be capturing my thoughts better.

> All I'm asking you to do is sincerely consider what your preferred course of action looks like if you are wrong about how effective each additional layer of controls are.

I am not a prophet (or a dictator). I'm an engineer. I see a potential solution or mitigation, I evaluate the trade-offs, and if it seems worthwhile, I suggest/try it. If it works out well, great. If not, I reevaluate everything based on the facts at that point. "I don't have any good idea anymore" is certainly a possibility I could reach, as is "I have another idea"...

Clearly there are a million factors to consider in each situation. Some predictable, some not. Just to list a few obvious ones off the top of my head: how fast we get there, how users react, how governments and lawmakers react, the magnitude of the scamming (not just rate! but also monetary amount), what other threats pop up in the meantime, what threats go away, what other mitigations or alternatives are available to try next, what the financial system even looks like at that point... these are all relevant. I can't predict what we should do in a vague, underspecified hypothetical where the only concrete premise seems to be that my predictions are wrong. (!) What I can see and suggest some solution for is the reality right now.