Until extremely recently, they did offer exactly such a service, though only in a handful of markets (mine was one). They called it Premium Lite. It was exactl

Until extremely recently, they did offer exactly such a service, though only in a handful of markets (mine was one). They called it Premium Lite. It was exactly what you want, a much lower priced subscription which just removed ads, and didn't include any other premium features. I happily paid for it. It was discontinued this month.