"Binge watching" is also weapon of Netflix demise: they drop the whole season at once, you watch it in a day or two, and then you forget it, and you never log in to Netflix again for several weeks. HBO dropping one episode at time creates a feeling of anticipation, and gives you a reason to keep your subscription always active, because every couple days there will be something new for you to watch..
then you forget it, and you never log in to Netflix again for several weeks.
But unless you actually cancel your subscription, that's not a bad thing for Netflix. All the time you're not in there watching content is time you're not consuming bandwidth or CPU cycles, etc. It's kinda like a gym: the perfect customer is somebody who signs up for a membership, and never shows up again, while keeping their membership active.
Now I know some people do the whole "binge for a while, cancel my subscription and come back in a couple of months thing." A good friend of mine actually does that. But I suspect most people are too lazy to bother, and keep their account active even when they aren't actively watching something. But maybe that's just me projecting? Hmmm...
Actually, I know many people who do this: create a temporary email address, register for a Netflix trial, and cancel it after you watched your favorite show. It's not really that much of the hassle, other than having to type in your credit card details when you register.
Netflix doesn't actually validate the email address you give them, so a limit per-email would do nothing. (I've had my email address be used by strangers signing up for a Netflix subscriptions on four separate occasions, each time by a different person).
I wonder if they would ever experiment with a lower cost membership that only has X hours of streaming per month. My favorite part of Netflix (and other streaming services that drop entire seasons at once) is that I can fit my viewing into my schedule. I may watch two episodes in one week because I have time that week, and then not watch anymore for two weeks as I'm busy with other things, only to return and watch 3 episodes at the start of the next month. A lower cost plan with a cap on hours would actually work well for me.