Actually, it's more related to design, but really it's an issue on its' own. Incompatibility exists due to the wide range of products available in any given category. Incompatibility often occurs as products evolve over their life span. Often new designs are simply diffrent rather than better and the design's usefulness often out lasts the product's life span. A product's life span is different from it's service life.
Service life is how long a product typically lasts in use.
The products' life span is how long it can be manufactured and marketed for profit. In the fast paced bicycle industry that's not long. So the various players go about romancing you for market share. You as a consumer must make very informed buying decisions. You must consider how every purchase will work within your current system.