Our philosophy on this topic, and I’ve offered commentary when this had come up before, is that we want there to be a definitive end point to character building. You should be able to look at a character some day and be able to say “yup, this character is done”.
On top of that, an endless progression system is incredibly punishing/discouraging to new/returning players. Nothing like knowing that the only way you’ll catch up to those who had been playing thousands of hours is to play thousands yourself (which effectively means you cannot catch up if they are also still playing).