This has been said before, but for at least half of the US, there are no options for Detroit style pizza.
And I think I'm being conservative when I say at least half.
I'm in KC, and as far as I know, my options are 1) Little Caesars 2) Pizza Hut. And I'm lucky that's there's even a Little Caesars within 30m of me, because they completely closed down all their locations here years ago.
It's 100 times easier finding St Louis style here than it is to find Detroit style
That's really the key to why Pizza Hut makes so much fucking money: they're fucking EVERYWHERE.