You mean you never received any major package update on arch ? 😛

More seriously, it depends on what we are talking about, if everything runs in container I agree that it kinda doesn't matter, you will just have a more up to date kernel, but it is stable enough.

Other peoples on this thread are talking about actual system dependancies, for example installing a postgres server from official repo. On this example it would require a database migration as soon as a major postgres version is released, which means some downtime and non-scheduled maintainance.