Grealish can barely move at 27, he's ancient!
Seriously though, of course he's not coming back, we can't afford him now even if he wanted to. But there are examples of players returning to sides and doing just fine.
Vidic, Van Dijk, Suarez, Cahill, Fernandes, Evra, Matic, Defoe, Coutinho (to Liverpool), Mahrez.
They all disagree with you.
But you need to spend big.
I agree, but yet whilst he was at Brighton he was the second coming of the midfield Christ apparently.
Brighton have had a very good scouting set up yes, but they are not some superhuman operation that need to be placed on a pedestal.
Considering they won't have seen each other for the best part of 2 weeks as of this morning I would find it hard to believe that they've even spoken, let alone fallen out.