True, I’ll add to that the compounded disappointment when you QT a fish for 6 weeks plus (ramping up copper, 2 rounds of prazi) and it still dies in the DT for another reason. Or a coral for 76 days and it flounders in the DT. And of course, carefully QTing and still ending up with vermitid armageddon .With this I would agree with you 100%
But the daunting task of running multiple QT tanks, can also chase many new aquarists(sp?) out of the hobby as well.
Many different ways to reef, choosing what works for you is the hardest part.