Here's a fun thought experiment as well. Would Tesla or Spacex be in operation today without Musk using his own personal money to fund them? The answer is no.
Another thought experiment might be, do you have enough information in that article to know whether that event actually happened?
Goalposts have gone and flown away into outer space I see. Musk wasn't talking about retroactive conditions of existence, he was evaluating worth in the present day based on employee absences. Aint nobody saying that the other paypal cofounders are essential to SpaceXs operation because without them Musk wouldn't have been able to have any paypal money in the first place because that is a stupid train of thought. And Musk certainly didn't evaluate whether his secretary was an essential element of his success over 12 years.
Hell, even if we were to accept your thought experiment as both valid and true, all it would show is that Musk's capital (not Musk himself) used to be essential to the company's operation. But anybody could have provided that capital, it's not like there's something unique about Musk's money that makes it more meaningful than someone else's. And his will/estate likely would have continued funding the company after his death so it still doesn't resolve his proposed test.
But more importantly, we can put aside all those factors because now his capital isn't necessary anymore so he would still fail his own test. So you would still be forced to admit that Musk brings no value at this time based on his logical reasoning / experiment. And even worse for your position, even if I did agree with you that Musk is essential to the company's continued operation because of his capital,
you could still apply his test to literally every other employee in the company and come up with the result that everyone but Musk is essential, which is a system of evaluation that is almost by definition, implicit hero worship.
"Hey, I'm going to evaluate my employees based on this cool test I made up that somehow always results in me being the only employee who works here with any worth or value. Huh, crazy how that worked out, weird. Oh well, that's just science and rationality, can't dispute it.".
And you complain about the veracity of the article as if we're reciting the narcissist's prayer, "Stop it guys, there's no proof Elon said this jeez, buuuuut...... if he did say it then he didn't say anything wrong. And if it was wrong, it wasn't that wrong to say. And if it was wrong to say, it's way better than other things he could have said. And even if its not better, that's just the reality of the world we live in so deal with it". Okay, so then why complain about whether he actually said it or not if there's nothing wrong with it. The only reason you're complaining about whether he said it is because the statement/story is so damaging.
Plus, I think it's a pretty safe assumption that he would treat his employees with less respect than his wife, and he certainly didn't refrain from treating his wife the same way.