That’s one thing I don’t love about Apple’s annual updates. Most users will just click that aggressive update notification and walk away.The problem is that Apple cannot control what light be problematic files, folders, etc. with third party applications. If one is meticulous about keeping such applications up to date, and doing associated disk maintenance, cleanup, and if needed, repairs, then most likely skipping two versions of the OS should be OK. The one instance, though, that would have had to most risk is when Apple implemented the APFS file system with High Sierra.
However, I’d assume most users that blindly click that button run their computers close to stock.