I have an intuitive aversion to this idea of taking out a loan and I suspect other people do as well. Exploring why we're averse to this idea could explain why it might be a bad idea to donate as much as possible now (or lead us to all take out loans).

I think an EA should actually bite the bullet and do exactly that, if they believe the rate of return is high. The reason why people (including myself) don't do it is because debt is considered a bad and a negative thing. Psychologically there is a big difference between having a positive or 0 balance vs a negative one.

As a separate point, it's very likely that the most effective strategy for EA movement as a whole is a mixed one.