Originally Posted by
JohnDThompson
It's a marketing tool, originated by Tulio Campagnolo and perfected by Shimano.
That's how it started, but I think it's become more than that...
With IP, companies have to develop their own "systems" which end up proprietary. Shimano developed STI indexing, which was protected IP. Campagnolo couldn't then sell a Shimano indexing system, they had to develop a campy indexing system. This leads to the gruppo bunkers.
It's not JUST marketing.