EXO prioritized earning public recognition with a traditional SM style song while SHINee looked to stand out and be unique. They're known for being non-SM in style. The only reason they were able to get their niche songs so popular was purely through their own talent and effort. And of course, there's a difference between being popular and being talented. It'd be more difficult for EXO to sing 'Evbd' than it would be for SHINee to sing 'Growl'. SHINee chose talents over public recognition. I think that's an accurate dissection.