DinoInDisguise
A russian spy disguised as a t-rex.
My guess, as with most things, is that there is a range in which things work well for most folks. And as you move farther and farther from that range it ejects more and more folks.
This can be balance or verisimilitude in games, music volume or temperature in a store, amount of spice in a food, etc...
I would be amazed to find that almost everyone didn't think some level of balance was needed (if we give all Wizards an extra level but no one else? Two extra levels? Ten?).
On the other hand I have a hard time imagining that "exact balance" in a game can be achieved without jettisoning a lot of things people like.
So the trial and error thing is to find those boundaries.
I think you are exactly right. I think the take away has to be that 5e is within the acceptable range for most players. And I think there is an argument that 4e was not.