Also I'm not comparing him as he doesn't have their talent, but De Bruyne and Salah failed at Chelsea. We seem to always buy player at their peak value instead of when they might be worth a gamble. If we'd bought Thauvin after he flopped at Newcastle we'd have had a productive RW the last 4 years. Probably not a star like he's been at Marseille, but far better than we've had there.
A failed move doesn't make someone trash, as we've seen with Tielemans, Lovren, going back Henry and Vieira and many other players. Lo Celso may well not suit Mourinho, but he won't suddenly be trash.
I think if we brought in some mobile, technically solid midfielders like Van de Beek and Lemar on a loan to join Pogba with one of McTominay or Fred holding we'd suddenly look decent in midfield, which would be a huge improvement. Imagine James being able to come off the bench to run at tired defenders, or 2 injuries or suspensions (let's say Pogba and Fred) still allowing us to field a midfield 5 of Rashford-Lemar-McTominay-VanDeBeek-James instead of the current situation.
Leicester are playing well, but even if you don't think they'll collapse 4th place is very open between Spurs, Chelsea, Arsenal and us and getting it might make signings and a manager easier to get, certainly worth a loan fee from our massive revenues.