Not true. There are plenty of cities in the US where you can buy a very nice house with several bedrooms in the 150k-250k range. You can get by with even less if you're willing to start with a fixer-upper. Totally doable for non-millionaires, especially if you're starting off with a mortgage as the OP described.

And plenty of people still seek roommates in these areas; lower housing costs also tend to correlate with lower wages and general cost of living, so it doesn't mean everyone is going to automatically live alone just because you're not in SF or NYC.