[budman1]

Not that many 50kw stations.

Efficiency is up, more in the upper 70%'s now days. (of course broadcasters will use a transmitter until it is unfixable, so there are some 50 year old units still on the air). Each user requires a 9 volt battery to listen (maybe a bit more...)

Compare that electricity with the streaming cost. The streamers computers and routers. The infrastructure cost for the internet (not all amortized to streaming, of course). The desktop / laptop / phone electricity for EACH user / subscriber.

Once you hit a certain audience size, broadcasting is more efficient.

Note: I agree with you on the billboard trucks. A waste.

[gosub100]

Yes, audience size is key. If there was only 50-100 listers (say late at night), does it make sense to run a 1kw microwave for each listener so they each can hear Nickelback?

I know it's more complicated than that, if they shut off the transmitter at night, they would lose listeners in total. I just think it's wasteful compared to other forms of communication.