A fiber-optic line connected to a cell-phone tower costs pretty much the same amount to maintain, regardless of how many bits happen to be flowing through it. By contrast, water and power companies actually have expenses that scale according to customers’ day-by-day usage.
On the one hand, I understand that a plan that gives everyone a free lunch can lead to overconsumption by a few, and once they use up the pipe that they share with me, my performance suffers. On the other hand, I wouldn’t want to have to think before opening every YouTube video, “hmm, is this going to put me over the limit?”
Not so much so. Many cellular towers still use copper T1/DS3 uplinks but even if they are fed by fiber you're still paying for a committed level of bandwidth from a provider. Your circuit may have a 1Gbit/sec capacity but it can be provisioned at any speed. If the cellular provider was previously paying for 100Mbit/sec of bandwidth and now they need 300Mbit/sec that's an expense of scale.
On the one hand, I understand that a plan that gives everyone a free lunch can lead to overconsumption by a few, and once they use up the pipe that they share with me, my performance suffers. On the other hand, I wouldn’t want to have to think before opening every YouTube video, “hmm, is this going to put me over the limit?”