I tried this in the past, it never worked. Resume spam is waaay better. That said it still is bad. In my whole life I got to technical interview stage only 8 times, and 2 of these were referrals...
Every time I've tailored a resume to a job I've at least gotten an initial screen. Tons of resume spam that resulted in silence though.
Everyone's experience is different but on average, tailoring has better results than spam.
Do you think the people who play the ATS game are doing it because they don't want to work at the place they're applying to?
That's a pretty specious conclusion.
No, it means they want to work but definitionally when you are sending out ad many applications as you can you stop caring about the individual qualities of a company - that comes later, when it becomes relevant.
As far as I can tell, the company in question (Claypot) has <10 employees. How many people do you think have even heard of them, let alone want to specifically work for them? Approximately all of their applicants are going to fall into the other bucket.
This chain is about "people who play the ats game" specifically, not claypot.