Because "internet" isn't a physical resource like electricity. Nothing is being consumed when you send 0s and 1s down the wire that's already been laid and paid for. When you load this webpage, it hasn't cost your ISP any additional money, so why do you want to pay them additional money?
ISPs' costs are a combination of fixed costs (hardware, labor, facilities, etc) and peak bandwidth capacity. They bill us in pricing that's a combination of a fixed base cost, and upgrade tiers that correspond to different peak bandwidth capacity. That's closer to "pay what you consume" in reality.
ISPs' costs are a combination of fixed costs (hardware, labor, facilities, etc) and peak bandwidth capacity. They bill us in pricing that's a combination of a fixed base cost, and upgrade tiers that correspond to different peak bandwidth capacity. That's closer to "pay what you consume" in reality.