This is never an issue with number of engineers, it's an issue of business priorities.

Large tech companies have plenty of engineers to fix bugs, but most of them are on projects trying to 10X things instead of paying down debt.

Apple used to be unique in it's immunity to it, they even shipped an OS update claiming it was only big fixes and not features which is unthinkable these days. Over time there's much less focus on polish from them though.