Comment by ASalazarMX

It's even simpler than that IMO. There are still nerds creating things out of love for creating something useful and clean, but as soon as it becomes successful, the smell of (potential) money attracts parasites, and they will eventually enshittificate the clean and useful thing if they get the chance, as they do with everything else.

It's the equivalent of the cycle of life: birth, maturity, decay, and death.