Good observation and question. Slot machines, in many respects, are like computers in that they have a hardware layer and a softeware layer. The box - sold by IGT - is the hardware layer equivalent to your computer and the game is the software layer.
The challenge that faces IGT is that they have run out of customers to buy boxes and now that there a lot of new companies who sell games - and much better ones then IGT - their profits are falling on the after market of the machines. AND the companies that exclusively created games now manufacture. So... their competitors not only are making money on the current boxes in the market, they are now making money when casino's upgrade.