Sounds like my job for the last 20 years. The guys who work hard pick up the slack for the guys who barly work at all. As a matter a fact sounds like every place I've ever worked in my life. And management just keeps leaning on the good guys because they have productivity goals to meet right now and its alot easier to lean on the good guys one more time than to go through the long agonizing task of trying to deal with the slackers so it never gets fixed.
Oh well, I gave up resenting it a couple years ago, accepted that's just the way it is and started happily counting the days to my rapidly approaching retirement instead.