the reason why it isn't already happening though, is there is a lot of people tied up with legacy wallet software especially exchanges and this doesn't benefit them in any way. it also doesn't benefit miners, it's purely a user benefit.
this is also why so many switched to knots, which is basically a bitcoin core fork, with some sane default policies, because core devs decided to fuck around with dropping a non-consensus policy that previously more or less limited extra data in transactions to 80 bytes. it is expensive data compared to per byte cost of witness data, so they rationalised "why not drop that since no spammer will use it" but that's kinda not going with the vibe of the thing.
