> They tend to happen because someone is trying to address a personal need
This I understand and do not contend.
> and decides to share their solution with the world
This is marketing, not necessarily for the money. It may be for recognition (yeah, I too know the "high" feeling when somebody comes to you and says you're doing something cool); for the hope that more people will join in so you get to be the leader; for having a non-trivial (hopefully) successful project to put on the CV; to feel yourself useful to the community, etc, etc.
Bottom line: when you make something publicly available, you're marketing it. You're "selling" your product in exchange for some of the immaterial goods (see above) that you can get only from other people.
This I understand and do not contend.
> and decides to share their solution with the world
This is marketing, not necessarily for the money. It may be for recognition (yeah, I too know the "high" feeling when somebody comes to you and says you're doing something cool); for the hope that more people will join in so you get to be the leader; for having a non-trivial (hopefully) successful project to put on the CV; to feel yourself useful to the community, etc, etc.
Bottom line: when you make something publicly available, you're marketing it. You're "selling" your product in exchange for some of the immaterial goods (see above) that you can get only from other people.