Effective altruists should be applauded for trying to bring evidence and reason to a subject that is plagued by far-mode thinking. But taking their ideas seriously quickly leads to a much more radical approach.

Feels like your sentence got cut off there, it should be followed by a colon and a summary of the approach. But I don't think that

So the true altruist will not merely create capital, he will make sure that capital will never get spent down.

is quite the approach you recommend.