Comment by zamadatix

Some things are easy to live patch, others are complex monsters.

The complex monsters tend to result in corner case considerations like "already open sockets cannot be upgraded but new ones will be" and a massive amount of testing to make sure the convenience saved is more than the risk of inconvenience due to some bug with a complex live patch.

Designing the whole system for live patching from day 1 can reduce the number of complex monsters but it's still more complex, and that's a ton of work (rebuild all or just shipping live patches) that could go into fixing other annoyances/limitations which are even mor inconvenient than rebooting for most users.

The result is some things support them in the most impactful cases, like certain types ofOS kernel updates, but most cases it's better to work on other conveniences instead.