To be fair to WAFs, most are more than just a pile of regexes. Things like detecting bot traffic - be it spammers or AI scrapers - are valuable (ESPECIALLY the AI scraper detection, because unlike search engines these things have zero context recognition or respect for robots.txt and will just happily go on and ingest very heavy endpoints), and the large CDN/WAF providers can do it even better because they can spot shit like automated port scanners, Metasploit or similar skiddie tooling across all the services that use them.
Honestly what I'd _love_ to see is AWS, GCE, Azure, Fastly, Cloudflare and Akamai band together and share information about such bad actors, compile evidence lists and file abuse reports against their ISP - or in case the ISP is a "bulletproof hoster" or certain enemy states, initiate enforcement actors like governments to get these bad ISPs disconnected from the Internet.