Corbyn might be popular but only because most voters are idiots. His ideas and his agenda would make the UK the most socialist nation in the western world.
Here's what he wants:
1. Nationalise Rail, Mail and the energy firms and take full control over the National Grid and the “policy functions” of regulator Ofgem.
2. 100 000 new council houses.
3. Thousands of homes opened to "rough sleepers".
4. Private rent capped at inflation.
5. £6billion extra for the NHS and £1.6billion extra for social care.
6. £5billion more for schools (effectively a reversal of the Tories cuts).
7. £250billion to an infrastructure programme.
8. Raise the corporation tax by £20billion and extra tax for private health firms and firms “with high numbers of staff on very high pay”. To actually accomplish what he says he wants done without running massive deficits year to year he will inevitably have to raise pretty much all taxes on everything and everyone to around 70%.
9. Free University.
He is so much to the left that there are no comparable parties in Europe to compare him to that don't have the word "communist" in it.
I'd like to see Labour return to a sane state, indeed.
I'm just glad that the Tories lost majority. After playing both sides on Brexit it is well deserved.
Most of those were mainstream centrist policies a few decades ago. The actual left wanted to go a whole lot further. Even the centrists nationalised a lot more than just those natural monopolies like the Royal Mail (e.g. car manufacturers - something which clearly didn't really work out, but at the time there was a desperate fear of losing jobs). Even Thatcher was OK with the Royal Mail being state-owned - was she a communist?
The problem is the rightward turn hasn't really worked out as advertised, particularly with regard to some of the more dubious privatisations.
With regard to the first one, our energy firms are already nationalised, it's just that its other nations who have nationalised them.
The real fly-in-the-ointment, it seems to me, is that Labour's support seems to come from incompatible groups. When you win both Euro-skeptic Sunderland and pro-remain Kensington (possibly, subject to recounts) you might find its because people are seeing what they want to see in you and you can't satisfy everyone.
(Incidentally, most Euro Communist parties aren't remotely communist, and haven't been for a long time. Most of them are about as communist as the Lib Dems. Many of them are consequently being eclipsed by actual left-wing parties.)
And the problem is, even if one has very little confidence a left-wing program could work, where is this 'sane' element in the Labour Party or in politics generally? How would such a 'sane' Labour party differ from the Lib Dems, who show little sign of recovering from their near-total collapse after being comprehensively taken for a ride by the Tories, or from the Blairites whose 'project' hit the rocks a long time ago?