Earlier quoted context omitted.
That is already implicit in the Efficient Market Hypothesis' valuation of the total market capitalisation of stocks (that is part of the reason for which the total value of the stock market exceeds GDP).
Right, but this chart ignores that (as far as I can tell). If US listed companies are going to eat more of the global GDP, then it wouldn't be crazy that the value of the stocks will exceed GDP of the country in which it's listed (i.e., the fact that the value does exceed GDP might not be a precursor to a crash).
Look at Amazon and Netflix, both tradin at 200x earnings. This is beacuse investors think they will earn a lot more in the future than they do now. Are they overvalued? who knows.