ISP routers have been more-or-less indistinguishable from switches for decades at this point. They're all "line rate" which is to say that regardless of features, packet size, etc they'll push traffic between interfaces at whatever the physical link is capable of without breaking a sweat.

In the case of Netflix it is in the ISPs best interest to let them push as much traffic to their customer eyeballs as possible. After all, it's much "easier" and cheaper to build out your internal fabric and network (which you have to do anyway for the traffic) than it is to buy and/or acquire transit to "the internet" for this level of traffic.