At work I learned "Slow is fast, Fast is slow".

We can always set all the versions to the "latest" and let it break when it does, but at scale that's not affordable.

Every module must be versioned and upgraded with care; Separate epic, Separate PR, code review and proper testing on different environment. This is basically why keeping the lights on is costy and some companies just rather to cope with old versions.

Then in an environment with lots of microservices, it's inevitable to avoid shared codes; So companies tend to hire lots of engineers just to take ownership of some services to keep the lights on.