It’s all the middle junk nobody wants which is why there’s so much of it.
Seriously tho, the historic context is that “The West” was west of the Mississippi river, which iirc got started calling that after the Louisiana Purchase. So the previous “west” wasn’t accurate enough so the states between the Mississippi and the Appalachian mountains (chiefly the northern states around the Great lakes). Then the area has just kind of expanded to include the plains states since they’re also flyover country
Pretty much, there’s some pretty clear distinction as well. Like you won’t find anyone on any part of a coast calling themself a midwesterner obv, but also the south east has the distinct trait of being The South, for better or worse. Usually worse. Southwest also gets a similar effect from being what everyone thinks of as “cowboy country”.
"Do you live in the Midwest?" by self-report (lemmy.world)