FWIW, I have a theory.
There are long, huge tunnels that are connected to one underground kitchen.
That’s why the food all tastes the same, in the places you mentioned.
You’re not missing anything. Trust me.
All these franchise deals are guided by MBAs from the same top schools.
If you want variety you definitely need to seek out the independent folks. And with the internet it’s much less of a crap shoot than in the old days if you’re traveling away from know territory.