I think Nintendo are trying to manage existing inventory so it lasts until the NX launch or sometimes before. I don't think they are interested in paying for new chip runs or setting up the foxconn wii u assembly lines again. They massively overproduced the console at the beginning and I think they are still using that inventory. It was estimated something like 12-14 million wii u's were produced and we haven't got to that figure yet in wii u sales I think. The white wii u production was stopped years ago but you still see some at retail.
Maybe Japan will be the first market to run dry. I don't think Nintendo wants to heavily discount the console either so again better to keep prices high by tricklefeeding to retail.
Normal procedure for failed consoles is massive discounting but you can see Nintendo aren't doing that. Hats off to Nintendo for cleverly dealing with limited demand.
