[bzbarsky]

> you pay for the amount of electricity you use, but you're free to plug in any appliance you want

You can get metered at different rates for different uses for electricity. A simple example I found just now is shown in https://www.eversource.com/content/docs/default-source/rates... (see Rate 1 vs Rate 5 vs Rate 18), but that sort of setup is pretty common.

Now, this is metering based on _type_ of use (heating vs hot water vs whatever else), not based on the manufacturer of your water heater. But to be a devil's advocate for a moment, this is the sort of thing ISPs _claim_ they want to do: prioritize certain _types_ of content over others. Now I don't believe them on this, of course...

But a priori, there is not necessarily a problem with an internet where you pay one rate for data streams that need certain bandwidth and latency guarantees and a different rate for ones that don't. That would be equivalent to the different-uses electrical billing above.