Alternatives to Adobe programs?

Adobe has nearly eliminated their competitors in most graphic design areas. In desktop publishing their main competitor to InDesign is Quark XPress (used to be very strong). In website design they have no competition at all, Microsoft Front Page does not mean anything now comparing to Dreamweaver. In illustration their Illustrator fights with Corel Draw, however most people are more comfortable in using Illustrator and that is why Corel looses its position. In photography there is only one king - Photoshop.
Are they any alternatives to Adobe programs? What is going to happen if Adobe becomes the most common graphic design software? By having no competition, can it maintain identical quality and drive for excellence? And what is going to happen to the price? Will it stay at the same level or simply continue upward. If you are the only one pizza shop in town, does it mean you can charge whatever you want for your double pepperoni?