So, if I get this right you want an alternative way to get +10s and +11s because the current methods rely on money (ingame or irl) too much. You want an alternative that requires dedication instead. A lot of people disagree because they simply don't want more +10s and +11s in the game. In their opinion a +9 is enough and you shouldn't even want a +10 or +11. However, if you do want one, you need to have a lot of money to get one.
I don't really know which side I should choose here '^' I also think a +9 is more than enough, that having a +10 or +11 is overkill... So I don't want more of them in the server than necessary. I do agree though that maybe the current methods of getting them aren't that great. Be rich or be lucky or no game. This really sucks for those players who don't have buttloads of money to spend on a powerup.
What these methods do though, is burn money. ED burner or blacksmithing, both take out ed/ec out of the supply. Considering how much ed we players have in total, that's sorely needed. Your suggestion will probably flop because you want to take this aspect away. Instead, your suggestion will only create more ed and will maybe even decrease the ed burning because people would rather do dungeons than pray to rngesus.
All in all, I think your idea is a valiant one, though flawed. The current ways of getting a +10 or +11 are imperfect indeed, but they are linked to something that the server needs. You could try to make your suggestion burn ed too, but it'd end up just like the current ways. I don't think there's a perfect option that will reward a person for their dedication while not fucking the server over at the same time. If you can find one, you'll get my +1 no problem. I don't think it's possible to make +10s and +11s more accessible without inflation or power creep though, so atm you'll get a -1.