I think the "plugins and widgets" path to making money easily ends up being detrimental to the original free thing. Instead of spending time just improving the thing, one ends up carefully planning out what can acceptably be broken out separately, how to make the thing extensible, billing, advertising, funneling...just all kinds of garbage.

Eventually you end up with a load of staff who are dependent on the thing for their livelihoods, and that influences decision-making. Next up is selling to a company with big resources "to empower us to complete the original vision" and soon after a new scrappy upstart releases their free alternative, to start the cycle again.