Yes. That’s not how it works.
It can actually be harder to perform and pull in numbers for a top team especially when you’re playing against parked buses 99% of the time, which clubs like Villa aren’t.
It’s like looking a Jesus at Arsenal (pretend he never played for us) and thinking ‘wow, he’d score 30 for us at least’ going off his performances for Arsenal.
Grealish was immense at Villa. Just because he comes to City he doesn’t start scoring or assisting with numbers on the level of Mahrez, Foden, Sterling or whatever. He’s even said himself how much harder it is performing at City’s level and that when he came he thought he’d bag loads.
The logic of your case just doesn’t work because otherwise we could just plonk a Watkins in our team for a fraction of the cost and get nearly the same result.
Ultimately Haaland gets the amount of goals he does because he’s the worlds best centre forward.