That's what happens when you're depending on sales based on nostalgia in a region where the product was never even released. I think a better gauge of its potential would be the NES GBA SP, but I'm not sure how well/poorly it sold.
The sales might have been better had Nintendo kept the Japanese packaging and the Mario logo on the back. I think most people interested in the Famicom Micro already knew about the slick package Japanese gamers got. American gamers deserve a NES Micro now that would be a special edition.