Joining at this point would require an insane effort on the UKs side. I am pretty sure that an undemocratic institution like the house of lords would not be acceptable under current EU laws and that is not even accounting for the UKs voting system. The UK would also have to join the currency union. The last point alone makes rejoining very unlikely in my opinion. I think the only thing UK citizens can realistically hope for is, at best, something similar to the Norway model.