Not really? The highest turnout for under 25s over the last 58 years was... in 2020 (~50%), when it was literally the same matchup . And that's still significantly lower than other age groups (62% 25-44, 71% 45+).

There was a small bump in 2008 (assuming you mean Obama), up to 49%. But in 2004 when John Kerry was the candidate the turnout was about 47% so not like. A huge change. And nobody remembers John Kerry.

Looking across the pond, in 2019 when Corbyn was head of the labor party and ran on a lot of lovely progressive issues, the turnout under 24s (they use slightly different brackets) was... Just over 50%

It kinda seems like young people just don't vote at very high rates, period. So it doesn't make a ton of sense to focus on them over other groups if you actually want to get elected and hold power.