It is bizarre. He couldn't hold down left wing at Valencia and the confidence that he is our answer at number 6 is just ... wonder what everyone knows that we don't
Use your eyes, you'd see how gifted and talented he is, and how good he could be. He's got the skillset needed to be a top midfielder.
He was starting games on the wing for Valencia until he got injured, and they had Soler vying for the same position in a 442. The odds were completely against him. Soler was their own player and an actual right midfielder unlike Pereira who was on loan, was being played out of position, and getting injured didn't help him too.
He has never been a 6, it was just Mourinho playing him there for the sake of it. You won't see many people advocating for him to be played there.
He's barely ever had a chance in the first team to play in a proper position that suits him. The only time he came close was with Granada and he was impressive in an underwhelming team, scoring five, assisting three and creating 52 chances, the fourth most of any U21 player in europe's big five and the most in La Liga - and that is just in terms of production and chances created.
No one is saying that he is great or that he is the answer to anything, just that he is obviously talented - even though some seem unable to figure it out - and should be giving chances to show what he can do in the right positions. The stars just doesn't seem to be aligning for him.