This tends to happen in every major bull market. The CEOs get an undeserved amount of credit. Nadella's been CEO only since 2014. Since then MSFT market cap gained $650 Billion in value. That's not all Nadella. It's simply the bull market and a strong economy boosting everyone's market cap.
The market keeps hitting new record highs and that's helping a lot of stocks
https://markets.businessinsider.com/news/stocks/stock-market...
On the flip side, CEOs tend to get an undeserved amount of blame during recessions and market declines.