Rupture Farms was simply shut down by Abe. It still exists but it has no one to run it. And no Glukkon is rich enough (or stupid enough) to take control over it on fear of the Chroniclers (basically the tax collectors of Oddworld).
However with the Shrink destroying Abe, just like the Glukkons a creature such as a Shrink depends on lower class followers to do their dirty work, as such creatures like Glukkons or Shrinks as they have no capable arms of such. So, they have no way of doing what they want. They need the lower classes.
EDIT: Damn you Xavier! You beat me to it!
Alcar...