I am honestly not sure where the mindset of Wario Land not having much demand to return is coming from, if anything it's become a key series that people like to point out in regards to neglected Nintendo series, to show off a few examples:
And speaking as the guy who's running a Wario Blog, yeah, people are disgruntled over the lack of a new Wario Land and they aren't afraid to get moody at you if you dare defend Ware or just be happy about small Land nods in other games, just because it's not the same thing as a new game, I had that happen several times.
Glowsquid already said the rest, Land is a successful series with a main character who remains popular and a constant sight in new games to this day, and Land related or inspired content is pretty much always well recieved, just because it doesn't have the most vocal following online compared to other games doesn't mean said following doesn't exist.
Also, all the platformers besides World and VB Wario Land are readily available on modern systems via the VC, so people even have a easy way to learn of the series and give it a chance even today and I have seen a number of people who got to play at least some of the Land games for the first time via the VC and became new fans that way.