There is tons of proprietary and commercial software available for Linux as well. Countless examples exist. Embedded, such as TiVo, NIT, TomTom, Sat. Receivers, Cars. And proprietary software is rampant on Linux as well. In fact, any website running Linux kernel with closed source software (e.g. PHP) on their server which you access with a web browser could be seen as proprietary software. It works just fine, right?
What ecosystem is the one you're talking about? I only see a few monopolies & big companies (Apple, Amazon, ..) mentioned, not a thriving ecosystem at all. In fact, I believe there's a much greater "ecosystem" around Gnome/Maemo than around the iPhone & "the iPhone clone army" -- e.g. I can open way more formats in my Maemo device (yet I agree maybe the most useless ones from a "average Joe" point of view).