Okay, I feel you now.
But it is important to say that back then, you didn't have to be a pop rapper or super mainstream to be considered successful.
Nas was considered successful & influential in Hip-Hop and that's what mattered at that time. It wasn't an underground or mixtape phenomenon.
As we know, Biggie changed that metric for east coast guys and it even affected Nas
That's why it's kinda hard to have this discussion in 2021 because what's considered "mainstream" & "popular" is so different than what it was in 1994
We already knew Mobb Deep existed before Illmatic.
They just had no direction and as Prodigy said, "The Infamous" wouldn't exist with Nas' influence.
And a lot of people checked for them because of his endorsement, which is opening doors, as I used Biggie opening doors for Jay-z as an example.
Jay-Z's older than Biggie and had a record deal and put out records before Biggie, but Biggie ended up showing Jay how to sell records, i.e. opened doors for him.