Lurked101 Problem is that Labour have a lot to make up from the last election, Corbyn is currently (according to the polls) more popular than Cameron.
I am very involved in local campaigning and local government from a cross party perspective. I know what is said on the doorstep; I hear it personally, and from canvassers from Labour, the LibDems and the Tories.
There is no upswing in support for Labour under Corbyn in our constituency wards nor the next two along. There just isn't. And we are in the North with a solid working class base that traditionally votes Labour.
All traditional Labour supporters in our constituency wards are concerned about is immigration, the EU and Brexit. And Corbyn does not attract swing voters. Indeed, privately, our local Labour members who live in the real world, rather than in a digital echo chamber, fear Corbyn will lose them controlling seats in May's election. One local Labour member who actually goes out canvassing reported that he has a hard time trying to persuade trad Labour voters from voting for UKIP.
Corbyn has attracted lots of support, from the young especially, I think the next election will be closer than you think, mainly because the Tories have started to do things for the advantage of a select group and is very blatant.
The idea is that young voters are going to appear out of the ether and vote for someone like Corbyn is a notion that has been around for years in radical left circles. I have heard it for years; it never happens -- not even after huge youth demonstrations or legislation that directly penalises youth lifestyles. The reality is that the youth vote can never compete against the over-30 vote, by virtue of the fact that it is a significantly smaller electoral pool.
The other thing you are missing is that while the Tories may be doing things for for the advantage of a select group, Labour is also perceived as being the same: i.e. the impression that they favour certain minorities and migrants over the British working class (in some cases, that they actively loathe the British working class). Corbyn has done nothing to correct this notion whatsoever; in fact, he has made it worse.
The only people to potentially gain in this scenario are the LibDems, but they are pretty much disastrous in terms of organisation and consistent messages at the moment.