Have Labour learned anything?

You don't need to.

This is due to a combination of the utter and obvious appallingness of the Tories, and our first past the post voting system. People get so desperate to remove the ruling party at almost any cost that they will vote for anything that might achieve that, however inadequate they think it is. Anything is better than what we have now tends to be the thinking whilst people know their votes probably wont count unless they vote for the main challenger based on the results last time. Under such circumstances the other parties all gain support where they are the strongest contender to the Tories which works heavily in Labours favour.

It nevertheless remains the case that most of their poll lead is entirely due to anti-Tory feelings and not widespread enthusiasm for Labour, and is therefore built on foundations of sand. It might just be enough to carry Labour over the line, but public support for Labour in office will quickly collapse once the Tories are gone and Labour offers little that is radically different but will indulge in an excess of top down control freakery as they are already doing inside their own party

Labour's haemorrhaging of votes since 1997 is a reflection of its haemorrhaging of working class Labour voters. The effects of this were masked for a time by the Tories losing voters too, and by the rise of UKIP as a challenger for right wing votes. That Corbyn won more votes in 2017 than at any time since 1997, and gained seats for the first and only time since then is conveniently forgotten by the pundits. That even in 2019 Labour under Corbyn gained more votes than Blair's Labour got in 2005, and actually had the largest vote share amongst working age people is also conveniently forgotten. 

What actually happened was that significant numbers of those who would formerly have been natural Labour supporters but who had given up in despair - particularly younger age groups and some of the working classes - came back. I know this was reflected inside the party by an influx of younger and also working class members, being one myself. But we were always treated almost  as an enemy within, as class enemies of the middle class careerist (they called it aspirational) Blairites who infested the party at every level. Corbyn's Labour seemed like a breath of fresh air to many of the millions the establishment chose to forget. Thats why he bucked the trend of decline for a time. But the tide was always against him on Brexit with the right wing vote uniting once more behind the Tories. And too many working class voters had already been irretrievably lost.

It is worth noting that there was very little reversion to Labour amongst the young and the working classes in Scotland though. The SNP had already stolen the crown of genuine radicalism which Labour had discarded. So whilst south of the border young idealists and working class radicals were in some measure inspired by Corbyn's Labour - the 2017 policies were hugely popular when people were asked about them in polling - north of the border they stayed solidly behind the SNP.

Well there couldn't have been that much growth if people couldnt see it...

There is much nonsense in your post Vinny.  Honestly not worth the effort of pointing each one out.

I am struggling to understand the thrust of this thread.  Under Blair Labour won three elections in a row and IMHO made the UK a much better place, all from a broadly social democratic positioning.  It has lost every other election in the last 50 years or so.  Under Starmer it is moving back to a broadly social democratic position and appears likely to win the  next election. 

It appears to have learnt the lesson that you need to offer policies that enough people will vote for in order to deliver those policies and improve the country (as they see it). It is hard to see what you are criticising them for?? 

50 years of elections Vinny - 3 wins (all by Blair) loads of losses.

Now with Starmer moving the party back towards Blair's "Social Democrat" positioning, it looks like Labour will win again.  

It seems an odd conclusion to draw from the data that the route to electoral success is more socialism and less social democrat but you are free to draw that conclusion if you wish, Vinny. I guess it is up to those running Labour whether to take your advice or continue along what feels like a winning path to the next election.