From Nintendo's own official shipment data:
TP on NGC is the second worst selling Zelda game on Home Consoles excluding remakes/collections/remasters (missing on the table is Four Swords Adventures as Nintendo gave no data for that, so its <1m) 1,3m might not sound so bad when it had another version released on a system that sold faster than money, however I woudn't call those numbers "very well"
It sold very well for the circumstances. The fact is even Nintendo has admitted the art style for the Wind Waker was detrimental to sales, but wer in complete denial. I always thought it was a well known fact that TP got most of its hype from its art style. When did history start to be rewritten? I still remember all the polls about Wind Waker, all the threads on IGN.