That's an unfortunate consequence of the gameplay format the cast exists in.
The characters all represent a stage in a sense, with each (well, most) of them getting a unique microgame set and putting their own note on each stage with their own personalitys and even several running themes, such as Crygor and his many inventions, Mona always having a different job or Dribble and Spitz with their many alien encounters.
While that's all great, it unfortunatly means that the characters don't really exist outside of their own stages, everyone does his/her own thing in the one stage they have for themselves and that's where it pretty much ends.
Granted you can have characters meet within the different storys, which we have seen several times in the past, such as Mona appearing in Young Cricket's Smooth Moves story, but even that doesn't give a lot of room for meaningful interactions and the way the games are structured inherently secludes the cast from each other, the DIY tutorial was one time where they weren't restricted by any of that and I think it was handled quite nicely.