Maybe, but in the US, we can't deduct "sweat equity."

I probably do hundreds of thousands of dollars' worth of work, for free. It would be nice to be able to use some of that, as a tax break. It would be a drop in the bucket, compared to the monster breaks corporations get.

I would be more worried about rigidly defining "open source." We see battles on HN, about the definition of "open source." It could end up specifying something like only release of GPL-licensed code is allowed, which might seem OK, but that's sort of taking a "political" stance.

I release all my stuff MIT (usually). That's mainly because I don't care if anyone takes it, and gets rich (Fat chance, anyway. My stuff isn't that amazing), and I'm not interested in coercing anyone else to take my political stance. I just don't want some bunghole suing me for something out of my control.