I'm not disagreeing with you that it has degraded, however it was acquired almost 8 years ago at this point, and the software world has been turned on it's head in the last... 3?
Software generally degrades post-acquisition, I'm not denying that. Github has definitely degraded. I'm not sure I would agree that the core reason in this case is "the acquisition" and not "AI making software and free-CI-load demand 3-5 orders-of-magnitude higher than it was 3 years ago"