Just for the record: as a developer, I have done a ton of free software contributions. I pretty much didn't get anything from it, except people complaining or asking me to do even more for them, for free.
I don't know if that qualifies as "getting ripped off", but it's not exactly paying me either.
I can relate, but artists get treated even worse. It seems to be a thing with creatives. Musicians also get ripped off a lot, as do writers.
Developers seem to have a product that people can actually attach a value to, but art and music; not so much. They seem to be in different Venn circles.
In all of it, we do stuff because of the love of the craft. One of the deeper satisfactions, for me, is when folks appreciate my work (payment is almost irrelevant; except for "keeping score"). It's pretty infuriating, to have someone treat my work as if it is a cheap commodity. There's a famous Star Trek scene, where Scotty and his crew are being disciplined for a bar fight with some Klingons[0], and Scotty throws the first punch. I can relate.
I don't know if that qualifies as "getting ripped off", but it's not exactly paying me either.