I got Claude to make me the exact same graph a few weeks ago! I had hypothesized that we'd see a sharp drop off, instead what I found (as this project also shows) is a rather messy average trend of outages that has been going on for some time.

The graph being all nice before the Microsoft acquisition is a fun narrative, until you realize that some products (like actions, announced on October 16th, 2018) didn't exist and therefore had no outages. Easy to correct for by setting up start dates, but not done here. For the rest that did exist (API requests, Git ops, pages, etc) I figured they could just as easily be explained with GitHub improving their observability.

Sharply declining usage? I don't see the stats to back that up on https://bsky.jazco.dev/stats

Usage has absolutely declined from peak switching periods where inevitibly some users won't stick around, but that's to be expected. Most stats seem to be leveling off (which isn't exactly stable growth either so the rest of your points stand).