All the electrical steering columns designs I've seen have used redundant sensors (often groups of them) specifically for that reason. The physical steering wheel to the shaft is still a SPOF, but it's also a "dumb" part where the only failure cases are mechanical. Eliminating failures there is straightforward engineering.

Yeah, I should have spent an extra 10 seconds thinking of the problem here and I'd have realised you can have multiple sensors going to different software on one steering column...