"such DDOSes as you mention were common, such a scraping strategy would not have worked for the scraper at all"

They are common. The strategy works for the llm but not for the website owner or users who can't use a site during this attack.

The majority of sites are not handling AI fine. Getting Ddosed only part of the time is not acceptable. Countermeasures like blocking huge ranges can help but also lock out legimate users.