> As a side note, I’m horrified by the idea that there are people whose Netflix watching habit runs afoul of their ISP’s data cap

If he's sticking with UHD content on Netflix then 4-5 hours average per day per account per month would reach Comcast's 1TB monthly data cap.[1]

If there are multiple users on his account (e.g. him and his kids) then you're talking just 1-2 hours of Netflix streaming per person per day per month. The UHD subscription package for Netflix allows streaming on up to four devices simultaneously.

[1] https://www.netflix.com/HdToggle 7GB/hr for UHD content