There's a lot of baggage that comes with signing someone for £150m - look at the list of 100m+ transfers:
Neymar - Decent return for PSG but not what they'd have hoped and non-stop off pitch issues.
Mbappé - Constant drama about leaving, holding them over a barrell, seems to have turned into a bellend.
Coutinho - Complete disaster.
Hazard - Complete disaster.
Joao Felix - Atletico can't shift him, don't want to play him. Pretty close to a disaster.
Enzo Fernandez - TBC.
Griezmann - Disaster signing, back at Atletico 2 years later for 1/3 the price.
Grealish - Playing about as well as our existing options in his position after 18 months not performing.
Lukaku - Complete disaster.
Dembele - Complete disaster.
I look at that list of players and it doesn't make me excitied about putting another entry in there, even if the player is amazing. That would hold true for Bellingham or Kvaratskhelia or Gvardiol or anyone else we might get linked to.
Normally I'm one of those people who doesn't care about how much someone costs, it's not my money etc, but for some reason these top 10 in history, 100m+ fees almost always end in disaster and disappointment, no matter how good the player is or how good the team they're joining is. Obviously something about costing that much money effects things.
I can't deny those transfers haven't been successful but I dont think its quite that straight forward.
Neymar, won everything in the game. Impossible to be motivated to play for PSG who implode every season in the CL.
Mbappe, see above.
Coutinho, injury prone and joined a team all over the place on the pitch and off it.
Hazard, injury prone and lazy. His talent was never in question.
Felix, joined the worst possible team for his football. Showing his ability now hes away from Simeone.
Enzo, never worth that fee but it was his release clause.
Greiz, injury prone and joined a team all over the place on the pitch and off it.
Grealish, never worth that fee but it was his release clause. Is delivering for the team now but will never repay 100m.
Lukaku, has a very good record if you look at the stats but just never suited what Chelsea were trying to do.
Dembele, injury prone and lazy. His talent was never in question.
I don't have any concerns about Bellingham. He will never be able to "repay" his fee but if he comes in and gives us a decade of service like those before him e.g. Fernandinho and is part of a team that wins several titles, then that is good enough for me.
Bellingham, like Grealish before him is joining a team that is on and off the pitch a million miles away from the likes of PSG and Barca and that is proven in the performances each season.
It may take him 12mths to settle but its an almost guarantee that anyone joining City these days will be a success. Its just in the City DNA now.