Yeah, game jams are an awesome way to brute-force the ideas to come out and many a great titles have started out from jams. The project I'm working first came into being as an entry for a 48-hour jam back in March. I've continually worked on it since, with pauses here and there due to life stuff.

Celeste probably didn't have a Kickstarter because the studio behind it (Matt Makes Games) was already pretty mature, having already shipped hits like Towerfall. Contrast that to Hollow Knight's Team Cherry who basically had to bootstrap themselves throughout the development process with literally only 3 people.