Those are just the major brands. There's a lot more only available from mildly sketchy Chinese sites, most of it bad but some of it excellent. There are exotic customs that cost hundreds and sometimes even thousands of dollars. There's a significant hobbyist/DIY community as well, even open-source driver designs and firmwares.
I guess this is a model that can be applied to a lot of products/services - even for things like Job Search, apartment search etc, as long as the data is reliable and is in machine readable format. I forget the name of the site - few years ago, Google bought a site that helped people look for laptops, but instead of saying 8GB RAM, it said "run photoshop fast" or something like that.
