There’s also that guy on YouTube who updated the electricals in his original Model S with electricals from a 10 years later Model 3 Highland just by buying spare parts, and it was pretty doable with fairly basic and limited tools/public information.
So the complexity in this article is just a BMW/PHEV thing, not an EV thing.
And check some videos of what you have to do to swap the door-actuating motor (which gets guaranteed water ingress) in the front doors (yes, not the gullwings) of a Model X.