It's an English thing. They grossly over-value themselves, which is why, even though I don't completely agree with it, I can at least understand why Arsene doesn't buy too many English players.
Example of what you're saying : Jack Wilshere The lad got talent BUT the media/fans supporters are making him look like Messi and saying he's gonna be "The next big thing" he's only 19,he could be really pressured to perform well.
17M ? No way he's way too over-rated.