Mending exclusive to Vault loot

One of the things that in my opinion destabilize the minecraft progression the most is the Mending enchantment. Mostly the fact, that you can just buy this enchantment infinitely from villager for quite a low price (especially when lowering villager prices). I now that Mojang is attempting to partly solve this issue by making the Mending enchanted book only available only from swamp librarians. But I have a slightly different idea.
How about really keeping to the original idea of Mending being a treasure enchantment and making it part of the new Vault loot table. Maybe even make it guaranteed to drop there! All while removing it entirely from villager trades.
This would in my opinion make Mending a truly end-game thing, which players would really have to deserve. It wouldn't create that many problems in Multiplayer worlds, as the Vault can be opened by every player once (could be a problem if the Vault is breakable).
The result would be that the Trial Chambers would have an awesome unique one time reward, which would definitely encourage players to visit them! While keeping the other enchants available from villagers, so they would still be viable.

Each player would then have to think about what item they want to put Mending on and which ones they can just create anew once broken. Also the anvil could get used a lot more to actually repair items!