And then people will move to a new solution.

I think this is a pragmatist vs idealist debate. The pragmatic answer is that Anubis solves a problem now, and so it will be used until either it doesn't or a better solution presents itself. The idealist approach is that it's obvious that there's ways to get around Anubis, and so some people argue from there that it shouldn't be used. But the only other alternatives being offered are to either eat up the costs (in server resources or engineering time), or to go behind cloudflare with its own tradeoffs.