We’ve had dozens of zoonotic jumps with bird flu that we know about, and surely thousands that we don’t know about. The mere proximity of humans and birds (and birds and other mammals) means that you don’t need directed evolution. Random mutation + recombination with other strains of influenza already present in humans and animals means that a single “winning” combination will inevitably spillover again. And has trillions of opportunities to do so.

When virologists talk about the inevitability of pandemics, this is the exact mechanism that worries them.

Not doing the GoF work is absolutely no guarantee that you’ll avoid these strains. I’m not convinced it’s worth the energy either, but playing ostrich isn’t a viable alternative.