QuincyAbeyie
Identifying which player with a very limited track record (a single season in both cases) is going to have a breakout is as easy to identify as which company in the stock market is going to break through it's ATH.
It's always obvious in hindsight and ridiculous to claim that it's an error on the part of the clubs. Either you're speculating on who will, in which case you could just as well end up with someone who doesn't build on their previous season, or you're waiting for more information/evidence of sustained performance before you pull the trigger.