Comment by Vvector
Back in 2015, they were a quarter or two from bankruptcy, saved by the XBOX and Playstation contracts. Those years saw several significant layoffs, and talent leaving for greener pastures. Lisa Su has done a great job at rebuilding the company. But not in a position to hire 2000 engineers x few million comp (~$4 billion annually) even if there were people readily available.
"it'd still be a good investment." - that's definitely not a sure thing. Su isn't a risk taker, seems to prefer incremental growth, mainly focused on the CPU side.
Where does the idea that engineers cost "a few million" come from? You might pay that much to senior engineering management, big names who can attract other talent, but normal engineers cost much less than a million dollars a year.