Working on games with Unity for nearly a decade, the standard approach is to defer upgrading Unity as long as possible. Generally we stay on the old LTS (Long-term support) version until it’s no longer supported. Latest version and new LTS are very unstable with game crashing bugs on certain platforms that I had to spend weeks to track down and spend weeks to convince Unity QA there is actually a problem then wait for months to get it fixed. It’s better to just stay away from the latest and greatest, having other people do the demining.
Games aren't like other software. People are still playing Psychonauts even though it hasn't been updated in a decade. Double Fine doesn't have the resources to go in and update the game engine every year.
(I'd argue there's more room for this in non-game software as well, but certainly for games...)