I have bought 3 strikers this season. Their profiles are shown below. None of these strikers have scored enough goals. I have sold the the first two; the last striker is still in the team. He trains fast but has failed to impress so far. I have one striker that was from the previous season. He scored a few goals more that those 3 strikers, and seems to be performing better than those 3 strikers despite having the lowest quality (25) and being a slow trainer.
What could be the problem?