. . . but imagine if we could eliminate (say) Ebola in the wild monkey population by creating a virus infection that maybe gave them the sniffles for a couple of days but then conferred immunity.
That would be extremely difficult with most monkey populations. They run away from humans, for good reason. I understand the plan is to spread the infection with monkey grooming, but many species do not groom or touch other groups of monkeys. Groups are hostile toward one another.
I think this would impossible with bats and some other species that cause zoonotic diseases. I doubt there are many diseases that could be targeted with this technique.
There are some similar approaches that do work, even with species that people cannot approach. Even with species with billions of members. For example, distributing DNA modified male mosquitoes has produced promising results. Their offspring do not survive.
Then again . . . maybe they do survive:
Big Pharma obviously won't support the idea of a vaccine that is distributed free of charge around the world
Oh, I think they would love it! "Free of charge" or not, they get paid. This reminds me of arguments against alternative energy, that big corporations such as GE don't want wind turbines and the like because they cost so much. Or because it would cost trillions of dollars to prevent global warming. On the contrary, GE would love to see governments spend trillions to prevent global warming. Who do you think would get those trillions of dollars? The money will not be wire transferred to Mars. It will be spent right here.
Every expense is someone else's profit.