@Vongola_Boss_XI:
If it weren't a mystery Oda wouldn't have been as vague and he wouldn't have had Roger be the only person to reach Lodestar in centuries.
Why is it so hard to simply follow the log path to the extent that Lodestar was widely believed to be the mythic final island?
It makes sense for Laugh Tale to be unreachable because the Road Poneglyphs are required. No one before Roger was able to assemble the full message and find a person capable of deciphering the stones.
It's unfounded to say Oda abandoned plans for Lodestar. If he had, he wouldn't have ben so vague, nor would he continue to build the lore surrounding the island.
He did not, that scene is basically Oda telling us that LaughTale is not the last Island and that the last island is not the main goal for the crew, the path they are on right now will lead them to what they really want(LaughTale), following the Log will lead them to Lodestar which will be a waste of time since what lies in there is something they already know.
Can they go there? Sure. But Oda is telling us is kinda pointless right now.