I suppose a company can not be PURELY open source software & hardware, otherwise making a profit would be very difficult, especially with the globalized economy. The Chinese will always make it faster, cheaper, and although not the best, good enough.
Plenty of bootstrapped microcontroller modules are out in the market. Why did Arduino catch on so immensely? My guess: low cost, the choice of a common language (C), floating point math, analog-to-digital converters (missing in basic stamp) & other peripherals, a very good forum, and "open source". But the same can be said about leaflabs.com, so what is it about Arduino? How did they make it into Radio Shack stores?