> Netflix also removes movies, some of them classics, after some time. So when my wife says she would like to watch something she's been wanting to watch, and I look it up, I find that it used to be on Netflix but it's not there anymore

This is a different matter. Netflix has a finite budget to license content. It's not clear that it would be better for the consumer if they had a policy of never removing films from the library, as this would have to be counterbalanced by fewer new films being added. I suspect this approach would be much worse for the consumer overall.

Also, unlike when a series is cancelled, those films are still available to stream on an à la carte basis from Google/Amazon/iTunes/etc.