The main problem for Democrats among this cohort isn't college students flipping to Republicans, it's college students not showing up to vote. Remember that Obama was very successful in getting younger voters to show up to vote, whereas Hillary wasn't nearly as successful in this regard. I'm not sure how well Biden will fare, given how relatively unappealing his policy platform is to younger voters (As things stand right now, I currently plan to vote for Biden in November, but I do not plan to "go the extra mile" for him by trying to get others to vote for him as well.)
This is the misconception though that polls keep getting wrong. It has nothing to do with Biden. Most young people will be motivated enough to vote because of how bad Trump is, not b/c of Biden. I think Biden will fare fine, and probably better than HRC, b/c young voters will be motivated by their hate of Trump. Just look at 2018.
It'd be nice if you went the extra mile though. I know I will. If you really care about Trump being defeated, you would too.
