I think that it's in part because he's taken the "easy" route (as he should have). This is hard to put into the right words so bare with me
By going for the gear demos, the magazine columns and so on, he's diluted his potential to be a star, as a lot of folks will never see past the "jobbing guitarist" image. There's no impact when he plays, he's just "the guy from [the magazine] Guitar Techniques
". The UK audience have heard it all before in a vehicle that doesn't let him showcase what he does. However this is what lets him play guitar for a living, rather than sitting at a computer behind a desk all day, but to get to star like proportions he'd need to up sticks to the USA.
Also, there's no market for a "guitar super
hero" anymore. When folks like us were young it was cool to be able to play your socks off, these days, it's how low can you sling your PRS singlecut
These are the guitar heroes worshipped by most kids today.
I'm personally not too fond of his own stuff, I don't find his melodies particularly catchy which is something I like to hear in with the great technique and cool tone. That doesn't mean he's not a great player though. I think he'll end up being more of an Allan Holdsworth than a Joe Satriani. And in a roundabout way that's a compliment