Peach got only one game. It's a good one, and we do need a sequel for it, but I just don't see it happening any time soon. Wario also doesn't have a new Wario Land in over a decade now I believe, but WarioWare's still a success and ongoing.
I'm not sure what kind of material Daisy can really use to have a game for herself. In all likeliness, it'll probably be Peach's game but with Daisy as a co-star. It can be a good opportunity to then have Daisy have her own abilities and stand-out traits that can get her star in her own game. I don't think she's popular enough to get her own game compared to Peach, though.
Pauline is in the same spot. Sure, she's the mayor of New Donk City (which I rather they continue that route compared to relegating her to a prize and a plot device, yuck) and you can get some game ideas; what if Pauline is the star of some Mario-eqsue Sim City game? But like, with Daisy, you probably need a new genre for games starring her and Nintendo just doesn't take those kinds as moves as often.
I doubt Waluigi will get his own game. They can't even be arsed to use him beyond a cameo in Odyssey, and after, what, over two decades? Waluigi's had golden opportunities that were blown (Mario & Luigi 4 was a major one imo) where I'd just be pessimistic and say if he can't get any sort of role in the mainline games or in WarioWare (that would be perfect), what makes you think he can get his own series?