Several of us have made this point several times, Loki, and you appear to be glossing over it: the Third Way/New Labour direction made Labour electable in 1997, but it also got them voted out in 2010. Are you saying that Brown standing again or David Milliband or Yvette Cooper or any other big-name Labour centrist would've got them back in again straight away?
New Labour/Blair/Brown are the very reason why people say Labour crashed the economy and can't be trusted to run it.
Conversely, genuinely socialist politicians haven't had a say in the running of this country for 40 years. And it's not like Corbyn was proposing anything particularly radical or "hard Left" as the Right and Centre like to make out. He was proposing measures and policies that Scandinavian countries have put into practice to the massive benefit of their populations, and get lauded here as "social democratic".
What Labour also need to do next time is challenge this absolute lie that the Tories are good at managing the economy. They're clearly not, when they adopt an austerity approach that assumes that all public spending is 50% waste, ignoring the principle of fiscal multipliers where there's actually a return on investment that feeds back into the economy, or prevents greater expenditure. They've actually shrunk the economy and its ability to regenerate itself by treating a country like it was a company.
Case in point: flood defences. The Tories in their fiscal wisdom decided to cut back on those, and what happened? Floods. Which did damage. Which the government then had to spend eight times the amount they tried to save in order to fix it.
The NHS demonstrably returns on investment. As does welfare. And the Tories cut back on both of those.
Labour as they currently are also need to really re-think their manifesto. It was too much, especially as they hadn't done anything to challenge the perception that Labour are profligate and irresponsible in government. They should've gone down the route of strategic investment, cutting back on certain things and investing in others. That's what Portugal did, and guess how their economy's doing now?