Some interventions have no impact, some have low impact, and some have high impact. 'No impact' doesn't help anyone/do any good, 'low impact' helps some people/does some good, and 'high impact' helps a lot of people/does a lot of good. Because of the size of the future, an intervention has to help a lot of people/do a lot of good to be 'high-impact' - helping millions or billions rather than thousands or tens of thousands.

We're fairly sure that AMF is 'low impact', since we have evidence that it reliably helps a decent number of present people. Which is great - it's not 'no impact'! But it's unlikely that it will be 'high impact'.

I agree that we don't have a clear sense yet of which interventions are actually high-impact. That's why I don't donate to any direct x-risk reduction effort. However the appropriate response to this problem seems to be to invest in more research, to work out which interventions will plausibly be high-impact. Alternatively, one could invest in improving one's position to be able to purchase more of the high-impact intervention when we have a clearer view of what that is - putting oneself one a good career path or building an effective movement.

I don't understand why you think the response should be to purchase low-impact interventions.