When I started to work on PLC4X I was hoping people would be using it to build commercial applications and either making money with it, saving money or building better products. That's why I stronly believe in the Apache License and am not a GPL advocate.

However I would never have expected that allmost nothing is returned by anyone.

I mean, I'm an IT consultant and I was doing consulting with other projects that I work on and I'm fine with that. I love doing that, I love giving training, mentoring people and companies to become open-source contributors. I saw that the effort-to-improvement-ratio open-source could bring to the automation industry was just incredible 5 years ago. That's why I put so much work into the project and I continue doing so ... just differently ;-)

We're getting into technicalities here, but in my opinion the ethical thing to do is to share your code freely for everyone else to use, however at the same time use a license that requires them to do the same with any code they derive from yours. This is absolutely nothing new, ref. the GPL.