I have no idea what you mean when you say that no one saw that he intentonally danced as Mako's frame.
Because that is not what has happened imho.
The Main Judge saw it, Hyodo's mom saw it (and both pointed it out too). The other Judge with the glasses noticed in his own way but couldn't quite grasp how it was possible for Tatara to disappear like that..
It just means he's not a professional. People have different amounts of stamina - he could've danced for 5 years and still not last till the end. Maybe he never made it to the finals before? All of a sudden, he has to dance 4-6 more times - something like that would show sooner or later. On top of that, how much experience could a child like him have - he's what... 16 or something, at most?and that he was actually a first timer with less than a year of dancing under his belt, which they should've known seeing how he lost stamina so quickly.
Just take a look at professional football for example.
These guys train every other day, several hours a day. 90m on the field is still really hard for them. Overtime will pretty much result in minor injuries for many of them.
I don't quite understand how Tatara's feats and talents relate to how bad the judges are.
Tatara is not a bad dancer and thus, he doesn't look like a beginner. This is what this show is all about after all.
He's a diamond in the rough, and that is not something that is easy to spot for everyone. Talent might be mistaken for experience, especially at his age.