The reason why Move It! hasn't sold very well is probably due to the fact is that came out with other games Mario Wonder, Mario RPG Remake and others so people didn't really care for it since they were bigger games. For Get it Together, I think it sold pretty well, especially consedering the sales of the game that came before it. Maybe if the game released in the early years of the Switch's life span then it would have sold more, but I'm not sure. I mean Smooth Moves and Touched are the highest selling games and they released really early for their respective consoles.
Move It was definitely a case of another game coming too quickly. Generally, the second WarioWare game on a system tends to underperform, as shown with Twisted and DIY.
Get It Together did fine, but maybe could have been released earlier on when there was more hype for the system.