It may well be that the electoral system locks Labour out all the same. Still, the thing about public anger is that it's directed at the current lot, regardless of who they are. I don't know if this would be enough to tip things in Corbyn's favour or not, and anyway there are still over three years to go until the next election, barring a highly unlikely early election.
Too early to say, in other words, but there are certainly scenarios in which Labour break through again in 2020.