Anyway "considered redundant backup not necessary for level 2 autonomy" breaks the "all Teslas now have the HW required for full autonomy" promise. They should have told customers.
There was V2, v2.5, V3. With both compute and camera improvements. It's pretty much expected that you will need some form of hw upgrade if your car is >2 years old when the FSD becomes a thing. And it's included in the pricing.
This powersteering unit now has a lot of field data about failures - they have 3M+ power steering units on the road.
So they may now have the confidence to put the powersteering into that category of "single redundant, but sufficiently reliable to be acceptable". Whereas before they had that data, it wasn't.
'Internally, Tesla employees said that adding “level 3” functionality, which would allow a driver to use their Tesla hands-free without steering in normal driving scenarios, would need the dual electronic control unit system and therefore require a retrofit at a service visit.'