A bot owners enshittification is a site admins salvation. The toggle is trivial to turn on or off. What will site admins do I wonder?
I don't think we will see Cloudflare enabling an "age assurance" requirement by default. I feel like I could trust them slightly more than a site operator, depending on how it's performed, but I also feel like it would be very easy for them to do much, much worse than any site operator, due to the inherent power of being a GAA. (Global Active Adversary, to those not familiar)
It's the same issue I have with laptops that aren't MacBooks -- you cannot always just fix an issue with a MacBook by choosing something else. Often, that something else lacks everything good about the MacBook and you'll have even more problems.
Also, not everyone has implicit trust in everyone else's future direction. No outsider could have known they would do this! The only reason you could've chosen them for it is if you already agreed with this default. It's entirely fair to push back against defaults you disagree with. Especially when stuff like this suddenly makes a majority of the internet way worse for users.
Note that I don't disagree with blocking bots in general, especially when you need it to prevent your site from crashing, etc. I disagree with making everyone have to opt out if they don't want to block bots like that. That will lead to most operators not doing anything, and most sites blocking bots by default, even when they never actually would have otherwise!