I'm no economist but I'm having a hard time grokking any meaning out of this metric.

So if Elon decided to sell all his shares today (and likely destroy his companies in the process), he'd shoot to the top of the list? What's the point in that?

My 401k has benefitted from the growth of e.g. Amazon for sure, but the main 'wealth' I get from them is my ability to buy anything and get it delivered in a day. That is, I benefit from their infrastructure existing, regardless of who the shareholders are.