With the slow and stagnating adoption of segwit it looks like it probably won't get adopted before the expiration date of 1 year.
So maybe miners simply don't see a need for it at least not yet. So I'm thinking that we will just see blocks staying full and clogging of the mempool until the average fees level peak causing adoption to slow down. Then miners will have to adopt some long term scaling solution otherwise their profits will stagnate.
It seems we might be a year or two away until blocks are permanently full with high fee transactions.