Right - but if you have, say, 1000 real user requests for those endpoints daily, and thirty million bot requests for those endpoints, the practical upshot of this approach is that none of the real users get to access that endpoint.
Yeah, at that point to might as well just turn off the servers. It's even cheaper at cutting off requests, and it'll serve just as many legitimate users.
No, it's not equal. These URLs might not be critical for users — they can still browse other parts of the site.
If rate limiting is implemented for, let’s say, 3% of URLs, then 97% of the website will still be usable during a DoS attack.
Right, but in terms of users ability to access those 3%, you might as well disable those endpoints entirely instead of rate limiting - much easier to implement, and has essentially the same effect on the availability of the endpoints to users.