"Are there not less expensive schools you can go to? "
At the moment, no. But in best Labour tradition, they've managed to produce a system that has all the things that are wrong with the market, without any of the things that are good about it.
By capping the fees artificially low, and offering universal loans for the total amount, for practical purposes every institution is able to charge the maximum (does anyone know of a degree-granting institution that doesn't charge maximum fees for home undergraduates?) So long as people regard the loans as a long-term never-never debt (and I realise that there are people who are dissuaded from going to university, but not enough to mean there isn't huge pressure on places, so it alters the balance rather than the total size of the cohort) the fees cease to be relevant so long as you can borrow the money. It's like house prices during the madness: no-one looked at the absolute size of the debt, so long as they could get a mortgage to cover it, so dropping interest rates drove house prices up to keep repayments constant.
This knocks on in turn to living costs, which are much higher than the figures you cite because every degree granting institution places pressure on housing in the surrounding area and drives prices up.
Suppose for the sake of argument the government set the cap on top-up fees at £10K or, indeed, removed the cap entirely. Clearly, the University of Nowhere is not going to be able to charge the same as the LSE any more. Now socially, that's a bad thing: it deprives the less affluent (or less willing to take on debt) of opportunity.
On the other hand, it will force out into the open the institutions whose degrees are arguably poor value for money even at the current costs (which isn't the LSE, let's face it). It also probably reduces student housing costs, because ultimately there isn't an infinite amount of money in the system and people trying to charge £500/mo for a room will find that even posh daddy is looking hard at £20K/yr fees+rent+living costs.
I think one of the failings of the current scheme is not that people end up owing £30K for good degrees. Those degrees are either worth that directly, or they are a life experience that's worth paying for. No, I think the problem is that people end up owing £30K for degrees that are of limited worth on every front, exactly the same as the people who win the lottery of life and get into the good places. Raising the cost of the best qualifications will enhance their value, which makes them more worth borrowing money for (I find this "less affluent are unwilling to borrow money" a bit 1930s: isn't one of the economic problems precisely that people are too willing to borrow money), whilst probably driving down the cost of more modest qualifications.
As social policy, it's shit, and requires the imposition of a good system of full grants for the less well off (which I think will probably happen). But at a nuts and bolt level of economics, it makes sense as a better way to manage demand.