It's actually one of the perks of centralized platforms like Reddit: if they want to, they have the technology and the resources to investigate bad actors like that. I don't just mean just finding and blocking their IPs, but untangling their ownership, corporate structure, tooling, and so on. Hiring actual PIs if necessary. It's the bread-and-butter for many spam and abuse teams at Big Tech.

That said, just because they can doesn't mean they will. It's possible that they've grown complacent and underfunded these capabilities (instead relying on community moderators to weed out bad actors). Or it's possible that they're too focused on the short term to see the existential risks. If I recall correctly, they couldn't resist the temptation of selling user content for LLM training, same as Stack Overflow.

But in an internet overrun by spam LLMs, the future are curated, walled-garden communities, and Reddit could be the basis for that.