So - let's take those one at a time, because they are interesting.
"Watching too much cable TV" - Cable TV is a broadcast Medium, and watching it, like listening to broadcast radio, has no marginal cost or impact. You can leave your TV off for an entire month, or tuned to a channel for 24x7x365 - zero difference in cost to the provider, or impact to other people on the service.
"Making too many local calls" - More than one person has been required to purchase a business line when they overused their local calling privileges. Indeed, on some CO to CO trunks, if enough people (ab)used their local calling privileges, the entire exchange would be blocked and nobody could call in/out. Unlike the case of internet connectivity, there is no graceful fallback - once the trunk reaches capacity, it's dead for anyone else. (Lumby, BC to Vernon, BC - used to happen all the time - 48 people could bring down a town of 1800). That's why those types of deployments require some type of per minute charges to avoid that scenario.
"If it causes degradation for other users, that's the fault of the ISP that has over-overprovisioned us" - We totally agree here. Any ISP selling unlimited service, and not clearly explaining how many gigabytes "Unlimited" equals, is doing everyone a disservice.
"Caps are just a way to squeeze out higher profits by reducing the necessity of upgrading infrastructure." - We disagree here. ISPs should provide Caps to their customers, and clearly communicate what they are - and then compete to provide higher caps while ensuring they maintain the line rate they've committed to their customers.
For example, if I've purchased a 1 Gigabit connection, the ISP darn well better invest in their infrastructure to make sure that none of their ports are blocking. Comcast utterly failed to do that with Netflix recently, and I find that annoying beyond belief. At the same time though, I don't expect Comcast to provision enough capacity to support all of their customers at 1 Gigabit (or whatever a high speed connection is) at the same time - that's cost prohibitive - particularly as it will rarely be happening.
On the Big I internet, this is solved by what's called 95th percentile billing. This is probably too confusing for the average user, so something simpler like, "You get a 1 Gigabit connection for $75/month, with a 10 Terabyte/month Limit during Peak hours, and Unlimited Terabyte limit in Off peak hours, $20/addition Terabyte in Peak, and we make sure that none of our upstream ports our blocked on any of our peering routers" is exactly what I'd be looking for.