It may not has to do with it
today, but it will tomorrow.
As I said, generating traffic is easy. If there is no drawbacks in raising streaming bandwidth on Netflix side, they will continue to do so, 4k streaming, multiple streams per account, YouKnowWhat... all the way until all ISP subscribers will use 100% of their available bandwidth at all time.
I may pay for a XXX Mbit/s access, but I know that no ISP can sustain that XXX limit for all customers at the same time. And I certainly don't want my ISP to shape my fiber access to 10kbit/s because that's the guarantied bandwidth they can offer me.
Note that I'm in Europe, I don't have an resentful/hateful relationship with my ISP, but I can understand the US case is different because cable companies (used to) have bad business practices.