I live in a "not affluent" city, and cashless is common. Many restaurants will not take cash. No hotels take cash. Some gas stations do not take cash. Grocery stores actively encourage cashless payments. etc...
Is it more likely that you frequent places which are cash-centric? Coffee shops, independent retailers and the like?
I'd be surprised if that were the norm in most places in the US. I have a $20 bill stuck in my wallet--which I carry mostly as a backup in case something goes wonky with my phone--but I mostly don't carry cash except on trips and I expect I'm more careful than many.
You'll find a strong blue/white collar divide here, which also tends to follow rural/urban lines.
Once you get into the trades and workshops, cash is king for obvious tax avoidance reasons. It's rare someone in such regions doesn't at least imply you can pay a portion of an invoice/bill with cash for a moderate discount.
Small shops in those areas might be more apt to only accept cash, and you'll notice at chain stores like Dollar Tree the cashiers actually have cash handling skills vs. the affluent areas of the cities.
For most places within the airline network, you can easily avoid paying cash these days. I still recommend anyone who travels keep enough cash on them to get back home in a pinch, if at all practical.
This is personal anecdote, but I make it a point to pay cash whenever at all possible (to the point of being "that guy" in my friend group) so I likely pay attention to it more than most.
Is it more likely that you frequent places which are cash-centric? Coffee shops, independent retailers and the like?