Royce after being out of MMA for years came back and went 1.5 hours with Sakuraba, and even won the first few rounds. By the time he fought Hughes he was 40 years old. Hughes was in his prime and in the middle of his best winning streak, also finishing GSP and BJ Penn. GSP only lasted 20 seconds longer than Royce did. By the time Hughes was 40, he was retired for years because he was losing to guys he should have beat. Age matters, it's not just the simple false narrative of 'no one knew BJJ back then".
Heck, in his second fight Royce tapped out Ken Shamrock, who was huge, strong, and did know how to grapple. Around the same time Royce tapped out Shamrock, Shamrock was beating legends like Funaki, Matt Hume, and Bas Rutten. All of those fights happened in a 10 month period.
Ken knew grappling? In later years he significantly improved his jj. Have you watched that fight - Ken tapped out of pure panic...
If prime Royce was magically transported from the 90s to now - he couldn't beat anyone above 135 - and some of those guys beat him too. That's not a knock -Royce provided a basis for which the sport jumped off from. Appreciate him for what he was.