Well, to answer your question is to answer mine. And, yes, there is an official timeline:

Here are the key differences.

It’s 2017 and you still don’t know what Nintendo’s focus is on. You should be embarrassed.

Stepmania (and most rhythm games) are a bit like reading English. You don’t see individual letters, you see words and sentences. In rhythm games, you don’t see individual arrows, you see shapes and patterns. Lots of practice gives you the muscle memory to be able to process those shapes and turn them into the motions…