They've been doing this for bloody ages, buying loads of talented young players, loaning the ones out who arent top echelon and then selling them for huge profits. This is just higher profile players and larger fees. It only works results wise if you have a proper strategy to the purchases and someone to bring them together on the field. For me I'm not sure that Pochettino will be able to do that, but he's going to get a good chance at it, both in terms of money to spent and time to bring an identity to a Chelsea team that has lacked one since Conte. I can't see them jettisoning another manager in a big hurry.