> A computer genetic algorithm run for a billion generations doesn't lead to anything anywhere near the the complexity of a human.

What?... Our computers can't simulate anything similar to a real world. You're comparing apples to galaxies.

> meaningful loss of fitness

What makes you think we don't have "loss of fitness" already?

150 years ago child mortality was around 30% in the developed world, now it's less than 1%. A lot of kids with weak health survive now. I'm one of them - I got pneumonia when I was ~2 y.o. and probably would have died without antibiotics. Then I had something which required antibiotic treatment pretty much every year. My wife also had a pneumonia in early childhood. And so did my daughter...

Why do we need to talk about some mysterious problem in 10 generations when modern medicine removes a lot of fitness pressure by itself?