This has the big advantage of not just increasing the raw number of "geniuses" but also the ratio of geniuses.
More people most of all means more people who can and necessarily will break things, which are very hard to repair. Like climate stuff. The chance of having some super geniuses, that we would otherwise have missed out on, who then repair a broken climate is ... vanishingly small.
I am more looking at the long term effects here, because I care about future generations too.
Another problem with your view is, that you are totally disregarding other species on planet Earth, which are going extinct or become endangered species in this very moment, in which we enjoy that our "condition is better than ever".
I don't think we're living on credit forever as productivity/technology has improved over time.
We have emission targets to return to year 2000 or year 1980s levels.
We can have similar targets for pops: 1900s or 1960s, before we had fast doublings of populations, obviously through natural reduction rather than forced.
https://aeon.co/essays/why-inequality-bothers-people-more-th...
(note of course I dont agree with everything said here)
The datapoint I linked to above would be completely impossible in a %P genius model.