In theory if there's a choice missing that consumers would prefer, some other company will step in and fill the void knowing customers will prefer their new offering.

In theory, yes. And it works for the easy things. But one does not simply walk into expensive electronics sector. Between capital requirements for product development and for marketing, it's really hard to make a viable product. People do try - there have been some bottom-up efforts for creating smartphones with features missing from the mainstream (ranging from security to customizability to openness), but they mostly failed.

What I'm saying is - voting with your wallet works for products where it's easy for a random entrepreneur to design a release a new, unique model focusing on unmet market needs. But smartphones are not such a product. Customers always choose out of available options, the difference is in how easy is for the market to iterate on different variants for different market subsegments.