I don't think that breaks net neutrality either, which the FCC seems to be reimplementing
Edit: see https://openconnect.netflix.com/en/
I think a few hundred GB for a typical cord-cut household is about right.
T-Mobile absolutely counts all data used over the network, my voice lines go QCI 9 (they are normally QCI 6) when over 50GB of any kind of data usage each month, the home internet lines are always QCI 9. I don't have congestion in my area so it does not affect my speeds. This is QoS prioritization that happens at physical sector level on the tower(s).
Imagine they put 10TB of flash memory on the satellites and run virtual machines for the big CDN companies (cloudflare, Google, Netflix etc).
I reckon that 10TB is still big enough to service a good little chunk of internet traffic.
You have to share that 10 TB with everything on that satellite's orbit.
Most ISPs have CND appliances in their racks to save on uplink bandwidth. And from a satellite perspective the uplink (in this scenario: the downlink from the satellite to the gateway) definitely is the expensive bottleneck.
You want to avoid congestion and every bit of caching could be helpful.
Then it comes down to the mass and power budget (and the reliability of flash drives in space) - but that doesn't seem too terrible.