There is no reason there can't be more Portlands or Minneapolises in the Midwest, for example. You take all those 2,500 to 40,000 communities and build around one or the other and soak up the surrounding communities to make bigger and richer communities.
As a rule, larger population center enables more and better cultural options, more and better education options, more and better industries and choice of jobs - There's a zillion of things that aren't feasible in a 100k city simply due to lack of scale.
In theory, sure. But in practice, there are a lot of reasons why there aren't (or won't) be more of those types of places.
The Midwest is strongly anti-city. In terms of culture, lifestyle, economics, politics, etc. Even self-described "urbanists" in the midwest are typically strongly anti-city (their goal is usually to reproduce the problems of existing cities, not to attempt any solutions).
It's not like there is a shortage of small cities in the Midwest. There's a reason no one is excited to move to Toledo, or Lansing, or South Bend.
I think if we look at what made these cities we can understand their current standing --but with effort they can change. Portland was not always Portland; Austin wasn't always Austin. People need to invest and put in effort to drive these places to where they want them. They sure don't have to be replicas of NYC or LA, or SF. They can bring to them what they find valuable while at the same time changing with the times to accommodate and attract or keep their youth as they move into the workforce from Uni.
They can transform these small-to-mid-sized cities into attractive cities with (youthful) Midwestern values.
Are you suggesting we should give up our right to chose where we want to live so you can have more small cities?
Perhaps there is compromise? Perhaps this is really only a real problem in SanFran and NYC. Even NYC has The Bronx and good rail service.
The problem isn't sparseness or density, it's a combination of readily available fossil fuels and mindset, I believe.
If the position is simply to oppose cars altogether, then I don't know where you can go. But I suppose you can find a bus to take you there...
And sure, some people do like living closer to nature. I acknowledge we have a nice core of people who love nature and land and cultivating the earth, what have you --they can still have their smaller ag-centered communities.