Just completely unnecessary ad hominem. Why?
The suburb I live in now has a literal "Main St" as well. Maybe it's an east coast thing, but saying he doesn't get out much was more a statement of fact. I can't think of anyone I've ever met who has never experienced a Main St, and the only people I can think of who might possibly meet that criteria are people who live in tiny rural towns that they never leave, aka people who don't get out much.
This is the uncharitable assumption which you didn't have to make. Someone was describing something they observed, you can counter them without making silly snide comments.
If it is a legitimate observation, they must really, literally, not get out much and I would recommend driving to the nearest town with a population north of 10,000 and look around a bit to broaden their horizons. That's the generous interpretation.
I understand it, though. There very much was a main street downtown in my college town. It wasn't literally called "main street", however.
Then again there are a lot of cities/towns on the east coast that predate the car, so there's probably an increased concentration of "main streets".