What does era have to do with it especially since some of the producers you named overlap?
If we are really being honest, I think a lot of people praise Grease over Swizz because of his early DMX work. A lot of Grease's work outside of X wasn't all that great. For example, he did work on I Am and Nastradamus, and his contributions to those albums were bottom tier. Best joint he did for Nas was "Wanna Play Rough" and it ended up on a compilation.
I Am and Nastradamous took part in that. Nas chose those beats to spit to. That's Nas fault to some extent. Those albums was Nas at his so called "worse"
Swizz is more hype than skill IMO.
Ny needed a super producer at that time