What really makes a national minimum wage increase insane is the difference in the cost of living in different places.
I moved to New Mexico from South Florida. I had a 1100 SF house that was valued at $465K and made $100K per year. We were frugal and basically still lived paycheck to paycheck. This was 2005.
We moved to New Mexico and bought a 3000 SF house for $300. Better schools and low crime (in Rio Rancho). We are currently making about $50K a year and live better than we did in South Florida.
$15 an hour is South Florida is chump change.
$15 an hour is pretty good pay in New Mexico.
A business will have no problems paying $15 an hour in South Florida.
$15 an hour minimum wage will put many businesses in New Mexico in bankruptcy.