I imagine people would be less likely to support bitcoin if they knew 1 company was producing hardware that could potentially dominate the network. Also, selling ASICs does not preclude them from using their own ASICs to mine.
Shoot if I ran a company that made the chips and the devices, I'd be hard pressed to sell any of them. I'd probably just setup a farm and maybe sell hosting. Screw all the headaches dealing with customers, customs, shipping, returns, etc.
I do know why they do it, someone has to hype BTC to increase its value. Targeting the geeks with new toys is a pretty slick way of doing it. Its pretty hilarious how much people will pay for this stuff though, for geeks you would thing they would be smarter than that. They must be spending daddy's money.. LOL