This is a win win for them. I don't think anybody has prime for just prime video. It's just an additional perk. The main perk is the free one day and two day shipping. Even if people stop watching prime video, they're mostly not going to cancel their prime because there are other perks they use. If they keep the membership but don't watch prime video, then that is resource savings for Amazon which translates to less operating costs. If they do watch it, that translates to ad revenue. Either way, win win. At this point there is pretty much no reason not to sail the high seas.