I'm one of the founders at Obsidian, and I definitely don't regret us supporting Linux on PoE. I'm admittedly biased as a Linux fanboy myself though.
We signed up to do it during our Kickstarter campaign as a stretch goal. I think [PoE's lead producer] Brandon's feeling was more from the trials and tribulations of setting it all up and problems we ran into during development. For example, it was harder to develop in Linux because Unity didn't support the tools at the time. Debugging was painful, but ultimately, we got it done, learned a bunch from the process, and now Linux is now fully supported in Unity. FWIIW, we don't have any plans to not continue developing on Linux!