In some U.S. cities, there are local laws requiring acceptance of cash by all businesses.

Outside tech bubbles, people are using more cash, not less. The Federal Reserve reports that U.S. currency in circulation has been steadily rising for decades, including the recent smartphone decade: https://fred.stlouisfed.org/series/CURRCIR

> Bills mandating cash acceptance have faced intensive lobbying from the credit card industry as well as more tech-focused retailers. The passage of the New Jersey legislation exemplifies such forces at work. The bill's sponsor specifically criticized a recent Visa initiative that rewarded 50 businesses with $10,000 each for making their operations cashless.

For the UK [1] (graph on page 2) shows the number of cash transactions made per year. There's a continual decline since 2012: "Since 2017 cash use had been declining by around 15% each year, so 2020 represented an acceleration of this decline ... Nevertheless, cash remained the second most frequently used payment method in the UK in 2020, being used for just under a fifth of the total number of payments made"

"At the same time there were 1.2 million consumers who mainly used cash, choosing this payment method when doing their day-to-day shopping (although the majority still use other payment methods to pay their regular bills). It should be noted that while these people prefer to use cash when paying for things, they are not necessarily unwilling or unable to use other methods of payment. The majority of them have a debit card"

[2] is the same for the USA (page 6). It shows similar cash use as the UK (1 in 5 transactions), plus credit cards used instead of debit cards.

For a much more cashless society, see Denmark [3]. Roughly a third of people don't carry any cash, and half carry less than 100kr ($15).

"There are differences in the use of cash between the youngest and the oldest Danes, but the tendency to move away from cash is seen in all age groups. In particular, senior citizens’ use of cash has declined in recent years: Among the 70 to 79-year-olds, 40 per cent of payments were made in cash in 2017. This figure was almost halved to 22 per cent in 2019.

"By comparison, the share of cash payments in physical trade fell from 9 per cent to 4 per cent among the 15 to 29-year-olds. Young people thus opt out of paying with cash in stores, but it is a change in behaviour among the oldest citizens which has been driving developments since 2017."

(Denmark has a national law requiring staffed businesses to accept cash, with some exceptions.)

[1] https://www.ukfinance.org.uk/sites/default/files/uploads/SUM...

[2] https://www.frbsf.org/wp-content/uploads/sites/7/2021-findin...

[3] https://www.nationalbanken.dk/en/publications/Documents/2020...

What’s a good example?

https://www.dwt.com/blogs/financial-services-law-advisor/201...

> though you wouldn't know it from the ubiquitous swiveling iPads at your local coffee shop, cash is the most frequent method of payment in the US – more frequent than electronic, credit, debit, or check payments.