Salary is one part of that, but unless you grew up in the area, most non-hub-city regions are a hard sell for young folk, and Detroit hasn't yet recovered enough to be "hip". People used to have for move specifically to find a job, but in tech there are so many jobs available currently that you kind of get your choice of destination if you're a capable engineer, especially with remote work available.
Because from my experiences in Australia and New Zealand, the majority of people work a 40 hour week. Everyone in my office has cleared out by 6 PM.
$50k a year for working 40 hours a week in the midwest with its lower cost of living sounds like a fine deal. Those kinds of wages are fairly normal for software developers to earn internationally in other developed countries like Australia or Germany.
I earn the equivalent of US$55k (plus bonus) here in Australia (I could be earning more, long story) as a relatively junior developer.
But then you have to add my annual leave entitlement, I get 4 weeks annual leave plus 2 weeks of public holidays (this country is so amazing, they give me a day off to watch the horse races). I hear that the standard in the USA is 2 weeks for a professional job. So I essentially get a 10% bonus in holiday pay. I also get 10 days of paid sick leave a year, and 3 days of bereavement leave for deaths of close relatives.
I also have 9.5% superannuation on top of my salary, and I don't have to pay health insurance. For the luxury of (almost) free healthcare, my tax burden is only $700 more than it would be in Grand Rapids. According to a random website I found, I'd be paying $3,000 per year for health insurance in Michigan [1].
So my income, adjusted for superannuation and annual leave, is around $67k, add the health insurance to that and I'm at $70k. Apparently cost of living in San Fransisco is about 40% higher than Melbourne [2], so on that comparison I'm not doing poorly, but Melbourne is about 20% more expensive than Grand Rapids [3]. I'm always skeptical of Numbeo though, because the numbers are quite off. Basically though, I have US$20k (plus bonus) per year of disposable income after I pay for food, rent, and utilities.
[1] https://www.valuepenguin.com/average-cost-of-health-insuranc...
[2] https://www.numbeo.com/cost-of-living/compare_cities.jsp?cou...
[3] https://www.numbeo.com/cost-of-living/compare_cities.jsp?cou...