I don't think the comparison there is entirely apt. Microsoft was really killed off by the cycle rate of desktops radically decreasing as even decade old machin

I don't think the comparison there is entirely apt. Microsoft was really killed off by the cycle rate of desktops radically decreasing as even decade old machines started to be good enough for everything except for extremely high performance usage like gaming, and mobile starting to advance enough to work as an alternative computing platform for many purposes. For direct competition in what was their bread and butter (desktop OS) - even Apple is still completely negligible. Musk's competition against the automotive and space industry companies has been very direct, and his competition against the petrol industry has been at most with one degree of separation. And like others have said, there is a huge short position against Tesla that has cost people an immense amount of money, but also stands to make them an immense amount of money if Tesla tanks.