Cloudflare's solution to every problem is to allow them to control more of the internet. What happens when they have enough control to do whatever they want? They could charge any price they want.
Giving bots a cryptographic identity would allow good bots to meaningfully have skin in the game and crawl with their reputation at stake. It's not a complete solution, but could be part of one. Though you can likely get the good parts from HTTP request signing alone, Cloudflare's additions to that seem fairly extraneous.
I honestly don't know what is a good solution. The status quo is certainly completely untenable. If we keep going like we are now, there won't be a web left to protect in a few years. It's worth keeping in mind that there's an opportunity cost, and even a bad solution may be preferrable to no solution at all.
... I say operating an independent web crawler.
You could combine that with some sort of IPFS/Bittorrent like system where you allow others to rehost your static content, indexed by the merkle hash of the content. That would allow users to donate bandwidth.
I really don't like the idea that you can get out of this by surveiling user agents more or distinguishing between "good" and "bad" bots which is a massive social problem.