Funny that you mentioned the sora thumb shifter. I was riding with a guy a couple of years ago who used to work for Shimano. He told me that the rumor that floated around the warehouse was that Shimano intentionally put that thumb shifter on their entry-level shifters to mock the Campy systems. Whether that is true or not, who knows? However, shimano has been trying to control the market ever since the SIS came out back in the 80's. back then, they even convinced manufacturers that their SIS could only be used on full Shimano drivetrains. Hogwash? Yes, but the manufacturers fell for it and Shimano laughed (and are still laughing) all the way to the bank.