Back to my question. Do current bees resist or tolerate varroa any better than bees 30 years ago did?
Is it all in the management? Pretty clearly the big traveling folks don't see any realistic way to get around using chemicals. This doesn't surprise me. If 95% of the cows in America were shipped to California every year, mixed together then shipped back across the 50 states, most of them would die of disease every year. They would also spread brucellosis and anthrax and tuberculosis and to every local cow they came close to. We would see lots of diseases that are merely minor problems explode into plagues.
The big surprise isn't that so many bees die, but that any bees survive.
Russian bees seem to survive perfectly well in their natural habitat, and in the US in anything similar to the natural habitat. Africanized bees survive perfectly well in the wild and resist varroa. If we packed 20,000 colonies of these bees onto trailers and shipped them to the almonds and back to Texas, and didn't treat them, would they survive? I doubt it.
My personal view, and I don't claim to be any sort of expert, is that concentration of colonies with movement to and from CA are the big problems. I don't see any easy way to fix those problems.