"Surge" is a bit of an overstatement...at best Labour will lose by 8-10 points instead of losing by 18-20 points - whihc likely means they will lose about 20 seats rather than losing 100 seats. No one seriously thinks there is the slightest possibility of Labour actually winning the election. IMHO, a lot of people in the UK don't want to see Theresa May waltz away with too big a win and have no serious opposition at all. We are a looooooong way from getting to a point where people start to think that Corbyn ebing PM is a serious possibility - we are still in the realm of "how big a landslide will the Tories get?"
Labour's problems are far deeper than Corbyn's personality or his "far left" policies.