But decreasing the average usage of customers, despite fixing maximum will mean profit. If somehow video sites get blocked, the average internet usage will very likely drop down many fold.
Without video many people could just stick with their cellphone bandwidth and drop their cable plan entirely.
Congratulations, you have just made anti Net Neutrality argument.
"Pissing off customers has failure points" is the core of the anti-NN arguments. There's no need to regulate what ISPs can do with the traffic - if they slow down access to some websites, or stop providing access to some of them or increase prices on the access of the "entire internet", then the customers would go to competitors who do not impose such restrictions.
The "there's no need to do last mile infrastructure multiple times" is bunk. It is easy, it is doable and no, you won't have 100 companies running lines. You would have 4-5 and that will be enough to push Comcasts and Verizon to get their prices down.
The issue is that the population of localities does not want competition. That's why the population does not want cell phone towers ( eyesore ), the population does not want more wires on poles (wires, eww!) etc etc etc. And the population wants to protect the busy bodies that attempt to block things ( because busy bodies are typically nice old people who should really be helped to remain in their homes and they really really really like stuff to be the same as it was fifty years ago ).
An ISP can leach off of internet traffic by shaping it so say Netflix is limited to low quality. But, that doesn't not mean they can simply block it without getting into issues. The problem is as demonstrated by China simply degrading websites bandwidth is is massive leverage.