I honestly can't relate and am confused who gets the work done then? Who supports the running software, who writes the code for new features, bug fixes and upg

I honestly can't relate and am confused who gets the work done then? Who supports the running software, who writes the code for new features, bug fixes and upgrades? Who works on planning and figuring out what to do or not do next? Who works to mentor and train and ramp up new employees? Who does the work to decide if we need to hire more, how we need to break up the work, where we need to invest more, etc? My work experience has always involved all of these things needing to get done and never having enough people to do all of it.