Eventually.
Vol 2 was 4x platinum in 5 months.
IDAHIH took 2.5 years to go 4x plat. Took 9 months to go triple plat.
Flesh took 2 years to go 3x plat.
Jay was the bigger artist at the time.
You still have to take into account X put out two number 1’s in the same year, the second one moving 600K first week. Only three rappers in the 90’s were able to put out two platinum albums in the same year. Pac, X, and Nas and only two of them debuted both albums at number 1, Pac and X and X is the only one who did it while alive.
I think the argument could be made for either of them OR a tie. Matter of fact if any two rappers were to ever “share” the crown it would be X & Jay in 98.
Somebody else said earlier it came down to who “carried themselves” with the attitude of a King and if we judge by that criteria then its Jay. X was more gutter and his persona was honestly that he couldn’t be bothered to give a fukk. Nas cared. Jay cared. Biggie cared. X didn’t have that persona even though he was well within his rights to.