Paying by check in the mail put a huge dent in this and then having the utility automatically debit your account pretty much put an end to it from what I've seen. I'm sure there are some areas where it still is a thing but they'd also have a high number of people without bank accounts.

For a while, utilities would only debit checking accounts, presumably because ACH payments are so much cheaper than credit card ones. A few years, they opened up to credit card payments. There seem to be a lot of people who do everything on credit cards and they must have had to change with the times.