Very true - few people who won hackathons went on to achieve big things because its a marathon not a 48 hour race. If they did 1 to 2 week competitions I'd be more interested
It's not just that. It's also because hackathons often favor the flashy over the feasible.
The one time I joined a hackathon, we came up with a solution that was low tech, cheap and easy to implement and added an analysis of the potential cost benefits. The winners said 'add a GPS beacon to everything and track it that way'. Which wasn't at all feasible, but it did sound cool and their demo looked cool.
I'm not surprised we didn't win, but the fact we lost from a flashy demo that would never be implemented was disappointing. Especially because it was an explicit requirement to be feasible.
Personally I love building things and seeing people use them, but then I get bored really quickly and tend to let them die out. It’s something I am actively working on because I do want to do another startup at some point in my career.