I'd claim that even voters aged below 25 have a right to their own mistakes (as did older voters in the referendum). But it really doesn't look like the young decided this election. But even if they did it doesn't really matter.
My point is that a Corbyn-influenced government might do just the kind of thing that UKIP and the Brexiteers (must have) had in mind without voicing it out loud (albeit in Corbyn's case without the right-wing outlook and damage & with possibly with less of 'neoliberal' thinking, WTM).
So what looks like a swing from one political extreme to another isn't really that great a change. Just as you said, Dave, people probably started looking at domestic issues. And Corbyn is, after all, the delivery on one of the many motives behind the Brexit referendum outcome, namely anti-establishment and focus on the 'disfranchised' (although I would never call them that).
Anyway, I don't know what Corbyn did in the 1970s. I was too young to understand. But that is 40 years ago and he should be given the benefit of the doubt. Who knows, maybe he brings some noise to the Brexit negotiation table on what has long been missing in the entire EU contract (although it won't have much effect, I'm afraid).
So, as I said, on a larger scale, it's an interesting development.
[Only an aside: Too bad that the UK couldn't have an anti-establishment type like Corbyn (needn't to be him) without having to buy into Brexit first. But there we go...]
[Another aside: Apart from that, I seem to be one of few people who don't see public spending as that big a problem. After all, it's the only logical step after/accompanying QE and a means to get money circulating. As for household consolidation, against a backdrop of QE and near zero interest rates, that is an issue that almost any politician should be able to alleviate somehow, unless stuck deep in the swamps for other reasons at the same time.]
