Simply put, +1 higher level club spent 2x less green to up their player quality. +2 level club spent 4x less green to train players. Not to mention they can buy 119% or 139% player with 1 token in the market.
It is nice and easy when u train bonus up to 10% and win over them and you feel like you are a genius in football management but reality is you are still playing against the odds and some season will come when few of them are very active and beat you soundless and you will open a thread to moan about it.