Price segmentation/discrimination. You can earn more if you sell at the maximum price that each customer is able or willing to pay, assuming it exceeds your cost of goods sold.

There are only 3 mobile networks in the US. But using MVNO, they can sell the same wireless broadband infrastructure to different people at different prices.

There is also QCI. You pay more, you (ideally) get higher priority.

https://www.reddit.com/r/NoContract/comments/tn4733/qci_leve...

https://en.wikipedia.org/wiki/QoS_Class_Identifier