Roger becoming Pirate King had absolutely nothing to do with Poneglyphs,
You guys are confusing between what We as Readers know, and what OP Public Know,
After Rocks Era, most Elite Pirates went on to try & Create an Empire for themselves (Everyone was No Different than Crocodile),
Except Roger Pirates who instead of settling down, decided to Journey around The World,
Do you know what that means? It means that while all those Great Pirates made it to International News, Roger Pirates were also making it to Local News all over The World, making them more Famous than anyone else, because They are known both Internationally & Locally anywhere,
Rocks & Similar Pirates = Pirate Activity that reached Worldwide Attention
Roger Pirates = Brought their Pirate Activity to every Area in The World
And Roger's Journey was during Garp's Era (Before it was Rocks Era & before that was Elbaph Era), but since Garp was Credited for taking down Rocks, it became an Era where Marines were seen as Dominant Force of Sea, not Pirate Island or Elbaph Giants, and most Pirates as I mentioned above were trying to create an Empire or Home, except Roger Pirates who managed to remain fully active & on the move for years & years without Garp or any Marine managing to Stop them,
Piracy = Sea Thief, and Roger Pirates were simply Best Thieves, because They targeted entire World & done it for many Years & Marines failed to Stop them, and it was this Journey that led People to say that Roger is Pirate King, because there is no better Pirate Career than that, this Crew proved that They can enter any place, take what they want & then escape safely,
As for One Piece Treasure, it's simply a Name given to what People believed to be Everything Roger collected during his Legendary Run, basically "Everything this World has to Offer", it's the ultimate treasure, so instead of repeating Roger's Career, Pirates in this Era want to directly find what Roger Collected & Hidden, to be considered his Successor & New Pirate King,
Plot Twist is that Roger didn't have any Treasure of his own, but He indeed discovered everything world has to offer, it's Joy Boy's Treasure.
So Overall, Yes, becoming Pirate King in this Era is different than what Roger did, but to say that Roger became Pirate King because of Poneglyphs is completely False, it absolutely had nothing to do with his Achievement, that's only a Plot Reveal meant for us Readers & those at the Top, but from People's Perspective, They gave him that Title & associated him with such Treasure, because He & his Crew indeed achieved The Ultimate Pirate Journey,