Then it also makes A/B testing unsuited to the task... Independence is a useful assumption, as it allows more tractable algorithms. It is a correct assumption?

Then it also makes A/B testing unsuited to the task... Independence is a useful assumption, as it allows more tractable algorithms. It is a correct assumption? No, obviously not, but it close enough to correct that the results you get from it are good. People have made plenty of money using A/B testing, which also makes an independence assumption, and people will make plenty of money using bandit algorithms. The only difference is they'll make more money using bandit algs.