Build a free bridge across a river, which allows a town to grow on the other side, then shut down free access to the bridge. The builders are entitled to do this, but doesn't make it the right thing to do.
For better or for worse, the success of many large open source projects is driven by a community of evangelists that just wouldn't exist if the project weren't open source in the first place.
The longer it runs, the more this is true.
If that is the case, wouldn’t that right also apply to the primary maintainer/owner of the copyright or is it just the users that have that privilege?
If I were concerned about somebody eventually monetizing a product that I contributed to, I wouldn’t contribute to anything.