What if you want to make a simple link previewer? An abstract crawler for scientific articles? Most websites are behind cloudflare which will block/captcha you, but happily whitelist only google & major social sites. Tha answer is measures that bring the web back to basics, not this over-SEOed bot infested ecosystem. FANGS succeeded in sucking out all the information of the web, but they suck at creating protocols that are interoperable (even twitter now needs its own tags!).
Incidentally, maybe the next search engine should use a push-system , where websites will ping to it whenever they have updates. If the engine has unique features, it might be actually seen as a measure to reduce the loads from bots.