sorry, I don't buy that the boards are really that expensive.
I've done custom development of products and the cost to produce a board and fill it with components is just not that high, even for small quantities (dozens), let alone larger quantities (hundreds or thousands)
the fact that third parties can make such cheap 'dev boards' including paying the profit margin of the third party board manufacturers, shipping between companies, etc.
In my opinion, they should not be looking to make a profit on development boards, they should view them as 'loss leaders', selling them as cheaply as possible to encourage more developers to use them. I'm not saying that they should loose money on them, but they should be at or close to break-even.