I think in 2021 there are still way more power users of Excel, and Excel is more important to more of Microsofts customers so they spend money to make it better. Lets remember, how many more 10s of thousands of devs work on Excel compared to Sheets? I want to say i remember seeing a news story that said microsoft was hiring an additional 25k or 36,000 devs to work on Excel.
I would have to google how to make a pivot table :)