I don't know about 100k. That seems small. I'm talking about metros of well over a million people.
But, also, don't get confused by looking only at the statistics for core cities. People look at, say, St. Louis, see that it has only 300k people, and stop there. But that's a wildly misleading number that's really more of a reflection of the fact that lots of people in the U.S. live in what are called "suburbs," even if those "suburbs" are actually still part of the urban core.
The St. Louis metro has 2.8 million people. 1.3 million of those people live in the core, urban city/county. That 300k number isn't useful at all. It's based on silly, irrelevant historical border-drawing.
But, also, don't get confused by looking only at the statistics for core cities. People look at, say, St. Louis, see that it has only 300k people, and stop there. But that's a wildly misleading number that's really more of a reflection of the fact that lots of people in the U.S. live in what are called "suburbs," even if those "suburbs" are actually still part of the urban core.
The St. Louis metro has 2.8 million people. 1.3 million of those people live in the core, urban city/county. That 300k number isn't useful at all. It's based on silly, irrelevant historical border-drawing.
The same can be said for most Rust Belt cities.