They've said they are introducing a reduced subscription fee with ads, not adding ads.
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.
They want to everyone, or the premier tiers. It's a conflict that can never be resolved.
Bottom line: if they think it will improve the bottom line, they will do it.