You don't even really have to "switch up", you just have to take what you do to the greatest lengths, its logical conclusion basically. Everyone's going to have different people in their top 5 or 10 or whatever, but for me Big Boi and Andre 3000 have certainly done that with their work, solo and together, from Stankonia until now. That is music that nobody else can do, lots of artists try to do, but Outkast have made it their sound and do it better than everyone that tries. That's why they are ahead of Em in GOAT talk for me.
You know, there is music that is timeless, that can be listened to at any time in history and be looked at as quality, defining music. Then there is music that is of-a-time, that you look at and remember that time and associate the music with that time. Eventually, the music of-a-time becomes sort of a joke, not taken seriously, analyzed as the reason something in the genre had to change. That's what Em's music is becoming.