That is such an overestimation of the reach and influence of the Twitter platform. People buy Teslas because they're awesome cars. People find out about Tesla because everyone and their brother has one. It started slow, you knew a guy who knew a guy, but they preached its praises. It slowly snowballed. They're to the point now, where you can't not find out about them. Twitter IMHO played a deminimus role in that. Normal people in the normal world aren't obsessing over Elon's tweets, or even reading about them.
Literally no one I know with Teslas (and it's many many) even using Twitter.
Furthermore, there are many other high-profile companies that are extremely well known that simply opt not to advertise. Look at Costco. There's no Twitter mouthpiece and no advertising yet everyone either shops there or knows about it, but doesn't shop there.