Would Xenoblade have sold as well as it did 15 years ago, on the DS? Or maybe 20 years ago, on Gamecube? Because that's the comparison you're making here. The circumstances are completely different, and we can't know if a new game in those franchises would do well because Nintendo won't make them.
I just don't share this view that Xenoblade was "saved" by the fans. The truth is Xenoblade got multiple chances, was made by a competent team and had enough funding. And that's exactly it: Nintendo's dead franchises don't get those opportunities. It has nothing to do with being dedicated to a game series or spending money, like has been implied in this thread. There's nothing to be dedicated to or to purchase, because these franchises have been dead for over 10 years. Good luck supporting that.
Completely separate from that argument is my wish for Monolith to make games besides Xenoblade, because I think it would result in better and more varied games. But that's sacrilege to Xenoblade fans apparently.