+1, I agree, I've been in touch with Nvidia quite a lot recently and it IS because they are so popular they have almost run out of stock, I had a small problem with my shield K1 got a RMA, as soon as they received it I got a new one withing 48 hours from the NL.
by the way if you get one please update to Marshmallow 6.0.1 then the patch that takes it to 6.0.2, now when I charge it to 100%, switch off, after 3 days switch it back on and it's still at 100%, before with lollipop the battery would run down from 100% to 75% in a matter of hours, and the compass had a lot to be desired but after the update all ok.
make sure you do a 3D compass calibration, after that you'll find the compass works 100%