Why do some people think Future Gohan...

[Papasmurf]

Not impossible no, but Future Trunks only noting that Gohan was a SSJ in the future and still lost miserably supports that Vegeta was pretty much a nobody in the future.

 

[p123]

Yep. Agreed with the group. I forgot the History of Trunks changed the time of Goku's death. Either way works, but Goku dying quickly after Yardrat, definitely could lead to Vegeta to lose motivation. Vegeta would now be the strongest in the universe and his desire to beat Goku is what forced him to improve. Vegeta barely improved his whole childhood, it wasn't until Goku surpassed him, did he become a beast.

I'm guessing that Piccolo's power didn't become haxed to fuck either in that timeline and Vegeta was probably still the strongest up until the Androids arrival. Must have been easy work for the Androids.

Also, this explains Gohan's situation. He becomes the legendary Super Saiyan and it's still not enough. Fits in good with the narrative.