Though I am doubtful, but I am willing to check out if a pre-heat cabin would reduce the need for heated steering wheel.
I came from a line of heated steering wheel ICE cars (last one of those was an Audi A8) to the Model S P85 back in 2014, before heated steering wheels were available on the Model S.
Pre-heating helps, certainly it does. If the whole cabin is toasty, which it definitely can get to given - say - half an hour, it doesn't really matter
that much if steering wheel can't be heated. It will feel colder to the touch, so not that luxury feel, but not necessarily cold.
Same with pre-cooling. It does not make leather(ette) suddenly nice and suitably cold to the touch, so it won't replace the need for good ventilated seats, but sure it helps a lot.
My Model X has both heated steering and ventilated seats and, given choice, I prefer it that way - they still serve a purpose when pre-heating/cooling is not practical (which for me seems to be often as I never seem to be able to plan when I leave exactly), yet even with pre-heating/cooling there is a reason for them...
Someone put it well, why heated steering wheel and ventilated seats are needed: even if the car is pre-heated or pre-cooled, the driver is not. If your hands are freezing when you get in the car - or you are sweatty after a run in the summer - having the ability to heat or cool the surfaces you touch is helpful, because it helps you personally reach a nicer temperature (or at least a sense of nicer temperature) sooner.
That's why some people like to set up a fire after coming in from the cold to the cabin and warm hands over it, even if the interior is warm in itself. Direct heat (or direct air in the form of fans in the summer) serves a different purpose than indirect one.
Always good to have the option, then.
Tesla's California background shows. The pre-heating is really an afterthought and seems like a byproduct of the pre-cooling feature. If Tesla lived and breathed cold climates, they would have started with pre-heating the windows (operating rear window heater as well as blowing maximum air at windows), then perhaps moved to pre-heating the seats and steering wheel over remote, but none of these can be done specifically remotely.
Indeed getting a Model S/X to maintain maximum blow on windows (those who live in cold know why) in a cold morning is hard if you need to step out to clear the windows... It just keeps turning off.
Yes, a California car.