trials are not about who's willing to partecipate, but about the best model available.
monkeys are not asked for consent, true, but they're not picked at random either, because it would be useless.
There's also another matter: who's gonna consent to participate to trials in your proposal, rich people or poorer people?
An finally, how would you ask for consent to monkeys?
Do you ask mosquitos to leave before killing them?
edit: what really baffles me about this discussions is how much the mood of the population swings.
We have seen literally revolts on the streets against COVID vaccines being a way to force untested drugs onto the people but at the same time people complain that there is too much testing on non people