The phrase “got tired “is not referring to the modern populations but rather the people who founded those original settlements in those states centuries ago.
They didn't "get tired", they found rich soil and ample water to do farming and milling, which is what they were intending to find. It's called the bread basket of America for a reason.
In some places, some people absolutely could not endure the long travels to the West Coast, for example the Oregon Trail was extremely difficult and many people quit somewhere in the middle and settled into those Midwestern states. Yes they did in fact get tired, in some situations.
What was so special about Oregon, anyway, that it was worth a deadly trek across the country to go there?
Wasn't it just that it wasn't yet settled, so you could settle there and claim some land? That implies that Indiana or anywhere else on the way would have been at least as desirable, but someone else got there first.
They farm corn and soy almost exclusively, because those are heavily subsidized by the USG. Most of America’s fruits and vegetables come from elsewhere.