Some very good points in this thread, one I'd like to add is demographics. Boomers have always had a significant demographic advantage over generations older than them, and younger than them. If you trace the baby boomer cohort through the decades, you will see how they're able to influence governments to be favourable to them, from housing to education, often at the expense of other generations.
There's a very good talk about this by Tory peer Lord David Willets - who has some good examples to this effect:
The Labour party has to come up with something that will apply to this demographic which they have polled low with since 2010. Or wait until they die off but that's going to be another 10-20 years.
Like most posters here my issue is I don't really know where Labour stand today. I knew where they stood with Corbyn, for better or worse, but where are they now? The reinvention hasn't happened yet or they haven't done a good job of communicating it.