Just like there is a carbon tax to care about making oil companies care about environment, the "Open Source Tax" would be a tax, that is applied to companies for using open source software, and re-distributed to foster open source ecosystem.
There does need to be a way to re-invest in open source software. I thought of an open source subscription before. But getting people to pay for it when it seems free....
Maybe there should be also research tax, cause researchers (esp. in public universities) create good for the public.