On the comparison of the Due with boards made by silicon vendors I think it's simply unfair.
Most (all) of these boards are sold either at cost or as a loss leader. Generally they do not a lot of work on the other elements of the equation or the simply copy us.
I can assure you that Arduino doesn't get any strategic pricing from ATMEL, the factories that make official arduino boards negotiate prices based on their sales.
About the Teensy. I think Paul did a great job. I won't elaborate on the pricing differences. There are many reasons for it.
Clearly the Due could be better in a number of areas like every product on earth. we could sit here and I could start finding things that I don't like about the Teensy, Chipkit and all the rest.
Judging Arduino just by looking at the hardware is a very narrow perspective on life... The project is the combination of multiple factors and it includes the work with do in documentation, keeping the IDE simple, working with the community on a lot of projects etc.