I would argue that Musk's Twitter obsession has an outsized effect because i) it is all over the news and even apolitical people get it ii) even a chunk of republicans find it weird (e.g., even Gutfeld on Fox is making unfavorable jokes about Musk) and iii) many Tesla buyers are left-leaning (in Europe, the mainstream is left of the US Democratic establishment), which means for core markets and demographics, a Tesla car can no longer be used as a status symbol.
Of course, the writing was on the wall without Musk buying Twitter: Teslas are now ordinary, mass-produced cars and traditional car manufactures catch up on electric. At the same time, electric cars are still mostly for relatively wealthy people, which means it is appealing to buy an electric car that's not a Tesla in order to stand out more.
I think your second paragraph is imperative. The question was always what Teslas headstart in EVs would mean. Fundamentally it might just turn out the answer is "not very much".
Of course, the writing was on the wall without Musk buying Twitter: Teslas are now ordinary, mass-produced cars and traditional car manufactures catch up on electric. At the same time, electric cars are still mostly for relatively wealthy people, which means it is appealing to buy an electric car that's not a Tesla in order to stand out more.