I didn't cancel Netflix yet (have been thinking about it as I find that sometimes I just watch it for hours, and it's kind of a waste of life). I can say for sure, if they introduce ads, I'm leaving, I won't pay for watching ads, sorry.
They want to everyone, or the premier tiers. It's a conflict that can never be resolved.
The fact that they drew a line in the sand is why I have brand loyalty. If they cross that line, I'll no longer be "supporting a company bringing a moral perspective on content delivery" and turn off autorenew: just pick up a month or two a year.
Bottom line: if they think it will improve the bottom line, they will do it.
Incidentally, all this talk of how badly they're doing just reminded me to cancel, which I did, minutes ago.