Why, just because he played for Florida State? Better receivers have come out of FSU and have never won a ring. I'll bet that had SF won you would be saying the very same thing about Randy Moss.
Hell, Boldin isn't even the best receiver on the Ravens team. Torrey Smith is a better WR than Boldin and I would even say that Dennis Pitta is a better receiver at TE than Boldin is a WR.