These HD remasters are for people that didn't play it before tho, not only from Nintendo but from everyone else, they're new games for those that haven't experience it yet.
People already interested will pay the $60 and will make up for the ones not paying, increasing profits in the end, that's just business, the reason others are not charging the same or more is because they can't, they don't have that much of a market strength they can exploit the same way.
But I guess their pricing strategy isn't only for short term profits, if they start pricing many of their old games lower, their "premium" perception will fall and those, with same or more quality than new releases, will cannibalize the later sales... Or that's how I think they interpret it, because some games no way will sell more at $60 than they would at $40 or $30.