We've bought several players from struggling teams in recent years - I don't think you can generalise. And you can't be sure how young players will respond either.
Gana was relegated with Aston Villa
Keane came from Burnley - finished 16th
Pickford was relegated with Sunderland
Sigurdsson was squeezed out of Spurs after they bought Eriksen (11.5 million GBP) and Lamella (30 million GBP) - amongst others - with the proceeds from the sale of Bale. I hope he will get a chance to show us what he can do this season.
The RS bought Robertson from relegated Hull and Leicester bought Maguire.
I wish we had bought them