I think it’s worth noting that Johnson’s 1000 yard seasons came during the Fitz era.
That said, I think it’s safe to say that if he was on a good team with a good QB, his numbers would have been top WR numbers.
But just taking the “if” game out of it, his stats are his stats. Everyone has garbage time stats.
No one has three 1000 yard seasons purely based on luck and /or circumstance.