The domestic player rule has a lot to do with that. It artificially inflates the value of middling English players, as you have to have a certain number of domestics and the supply of great ones is limited.
That "problem" is what you want at every position on the pitch. True all-worlders like Messi and Ronaldo push themselves far harder than any manager ever will and drive everyone else up to that level of intensity (or drive them out). If you're not fortunate enough to have one of those, then...
Someone (or some people) with money that they're totally comfortable with flushing down a toilet placed bets. If you understand how an oddsmaker operates, then it's the only explanation.