Current supply issues I believe are the reasons why those buying new and or needing a replacement are not fluid at the moment. Microsoft was terribly conservative with the Surface Pro 2 (after the lackluster buildup from Windows 8, Surface Pro 1 from major reviewers comparing [on the skin surface] it to the iPad). They did not think to make more than a few hundred thousands of devices past the pre-order amount (not wanting to again, eat the cost of things like they did with the Surface RT).
I would understand current supply issues, my gripe with MSFT is their customer service is horrible. I have been dealing with the AnswerTech's for over a week. They have elevated it to the customer care department which will contact me in 3-5 days which is ridiculous to say the least. If you don't have stock you could give me a potential date when product will ship versus nothing at all.