A few things at play here.
1. You aint supposed to still be relevant 16 years later. The shyt we have seen with Drake and to a lesser degree Jay aint the standard, its outlier shyt. How much acknowledgement does Rakim or KRS get? shyt how much were they getting in the 90s?
2. He made music that was hot for its time but not timeless. Not a lot of substance. Some straight up destructive BS in some of it. At the time he was the coolest thing on earth. But the folks that thought that in HS and college are now grown and look at it differently. We see him for the false flagging lame junkie he was and I say this as a person that fukked with his music.
3. The stuff that made him who he is the mixtape stuff that the mainstream isnt familiar with.
4. This probably the biggest thing...he never pivoted. He didnt have Snoops personality, versatility, or foresight. He didnt have Jays ruthless business sense, narrative understanding and influence, or famous spouse.