@Celestial D. Dragon Man.. Didn't you read the interview where Oda said that he at first wasn't sure if he should make Luffy the PK or pre timeskip Helmeppo?
After all it's just a scavenger hunt and you only need to collect bits of information here and there in order to find that treasure. Everyone can do that. Eaaaaaasy game.
People, just because you theoretically can think of scenarios where one finds the treasure independent of a certain power level, it does not mean that you are realistically able to do it that way and that solely finding the treasure makes people acknowledge you as the Pirate King.
The Pirate King is not an officially granted title by some sort of committee after finding the treasure. It's a title that represents the obstacles that you overcame in order to find that treasure.
On your journey you had to surpass the strongest people in the world, cause in practice people do not get to laugh tale just by sheer luck alone.
That's why Roger ended up as the strongest fucker around, only rivaled by Primebeard.
It was the product of his journey of becoming the PK, a journey where he actually overcame such obstacles.
And just because you know of 2 scenarios where Roger might have had luck, it doesn't change the fact that Roger factually ended up as the strongest man, who was acknowledged and mostly even respected by his enemies. Probably had to fight one time or the other, don't you think?
In theory you could possibly find laugh tale w/o all those struggles (close to impossible btw), but it's simply not what the title Pirate King stands for.
You even have Kaido and Big Mom telling us that they would be able to find the treasure if they combine their resources, but that they still would have to duke it out afterwards, in order to rightfully become the Pirate King.
Note: Normally Luffy would be the No1 in the verse as the PK. But I dunno what's up with Imu and if it's even legit to include him into all that. I mean I certainly wouldn't do it, if he's some kind of "special" god like being.