I suppose that's the question isn't it? Do good jobs become available because talented people are in an area, or is it something else that results in jobs being created? I'm inclined to think that if you plonked Cambridge University into Barnsley (for the sake of argument - they're similar'ish size towns), then Barnsley wouldn't have much of an unemployment problem. Education, whether degree level or otherwise, really is key imo, and not enough emphasis is given to it.
I'd have to guess its neither exclusively. I'm sure Cambridge benefits from having the best University in the country in terms of creating high paying jobs in that area. However lots of the people filling the high paying jobs in London are not natives, they were drawn there by the jobs on offer. Both the places I've used above are fairly unique examples, but what's not to say that other regions wouldn't benefit from a concerted effort to create good jobs there? The people will follow the money.
I agree education is vital, in even more than just an economic sense. But personally when I say 'good jobs' I don't just mean those which require formal education, I mean a job which allows the individual to meet their own needs. Not everyone will go to Uni or an equivalent form of education, for various reasons. The well educated workers require people to make them coffee, serve food, work in the retail stores they buy from, collect their rubbish, etc. Those jobs should pay enough to live on. Increasingly they don't. Resentment then creeps in, and UKIP et al capitalised on it very effectively.