I think 1997 was the last time Labour won an election because people actually wanted to vote for Labour.
I think Labour has long term problem appealing to enough people to win an election, after 1997 Labour has only won because they were the least worst option and the 2 times that Labour has had something to vote for, more people voted for the Conservatives.
So the problem that Labour has right now is something that's been a problem for a long time.