If you get up to mass-scale production quantities, $100 might be feasible. I imagine small-scale production with little up-front capital and no guaranteed market might be lot more challenging. It's not software, you're going to need large orders to get good prices.

I think about Meego/Jolla phone and tablet, Ubuntu Phone, Kobol Helios and tons of other projects that have either failed or are struggling due to market size and ecosystem.

I've been running a Turris Omnia for the last few years, which I've been fairly happy with. Network performance is about average and the platform as a whole is certainly due for an update, but stability has been great, it receives regular upgrades, and I'm happy to pay more for a project that has an open mindset. Not sure many feel the same way about commodity network hardware though.