I would think it's because of money. They would need a public performance license, which would cost about $500 a year, or $1500 for 3 squares so you could hear the live band at home.
The music publishing companies do their own enforcement. There was a bar in Tampa in 2016, Tadpoles Lounge that hired a band for playing on a holiday, and they didn't get a license, I believe it would been $1500. A few months later they got a bill for $300,000 from BMI. They eventually were told they could settle for $30,000, the owners couldn't afford that amount either and so they went out of business.
Currently there is a bar in Tampa and one in St. Pete that are being sued by ASCAP for not having a license.
Two Tampa Bay restaurants fined by ASCAP for not paying for music rights
Tadpoles out of business
