I'm not sure how old you are, but shortly after Obama took office in 2009 there was quite a bit of reporting claiming that the Bush administration had been so disastrous and young people had been so thoroughly poisoned by Republican policies, that it would likely be a generation before the Republicans had the chance to win the presidency again. Remember, Bush left office in the depths of the Great Recession. Instead, it took less than 8 years for us to get MAGA.
In 2024 Trump got some of the youth vote, still not a majority. Trump never won Gen X (or at least Millennial) and below.
So the prediction sounds right? The Republicans have burnt the youth vote pretty badly and have never really recovered.
In the 2024 election, Trump's strongest margins appear to have been with Gen X, where he was roughly +10% over Harris, even stronger than his results among the Baby Boomers.
(See, e.g. https://www.pewresearch.org/politics/2025/06/26/voting-patte... and https://www.nbcnews.com/politics/2024-elections/exit-polls. Annoyingly, the polls don't cleanly break down into generations; Gen X would be the ~44-60 crowd for that election.)