Part of this is likely driven by regulations. Github has plenty of clients that fall under DORA, NIS2 or both.

I don't remember the exact wording about what qualifies as "incident" or "major incident" but the TL;DR is that the regulated entities are required to notify their regulators of impactful supplier incidents within 24h with initial information and within 72h with more complete details.

Which in turn means that Github will have signed contracts that bind them to accommodating timelines.