Without the mention of FOSS, these types of pro-market "solutions" will always end up dead in the water.
This is not just a matter of competition for its own sake. This is about guaranteeing users the fundamental right to technological self-determination, a right that corporate monopolists will not yield willingly. This is nothing less than empowering users to seize the means of computation.
Can't have tech self-determination if everything's a black box controlled by corporate entities.
Libertarians open source (not free) because it ties into their idealistic notion of how individual freedom is true freedom. In the end software with open source licenses like MIT end up being free high-skill labour for megacorporations who don't give back, neither in terms of financial support nor code changes.
Libertarians love both proprietary and non-free open source licenses for this reason.