If we combine the market cap of the entire S&P500 we get close to 70T. That doesn't mean any of those individual companies are any more valuable or any of the investors are any richer. It makes no sense that Tesla shareholders would be ok with paying out a performance bonus just for M&A that doesn't grow the value of Tesla and would just dilute their shares.

I understand Tesla acquiring other companies counting to the cap, but Tesla _being acquired_ by another company, why would that count?