Yes, today's first time voters will be 5 years older next time and their views and priorities may change. But there are always new first timer voters at every election, the key is reaching out to them.
How was this a missed opportunity for Labour? Everyone had them down on the canvas, out for the count, 20 points behind in the polls. facing total obliteration etc. Would anyone have predicted this result a month ago? If it wasn't for some bizarre results in Scotland and fair few Tories hanging onto their seats by very narrow margins (just hundreds of votes in many cases), things could have ended up even more different.
The Labour Party needs to unite behind Corbyn now and I suspect it will. I'll hold my hands up and admit I wasn't his greatest fan before the election campaign, but I think he ran a great campaign, a good mix of old school getting out there on the stump and harnessing social media.. Now if he'd only campaigned with similar passion for Remain ......