You're not wrong, but everyone can probably agree he wasn't gifted like Randy Moss. He had a 4.65 shuttle time and, I'll add, there's a reason he played his college ball at Mississippi Valley State. He was what would be considered a 2-star recruit today. And yet he's probably regarded as the greatest receiver of all time, even ahead of Moss.
Obviously he had some physical gifts to go along with his work ethic, but what set him apart and made him Jerry Rice the legend was how he absolutely outworked everyone. His work ethic is stuff of football legend.
A lot of that "gliding," catching, and evading was because of confidence - he'd done it a million times before, he knew exactly where to go and when. He never hesitated or froze, he just moved, because he'd practiced every route and move a million times.
It's kind of like how you can have a linebacker with incredible speed and another who is a bit slower, but if the slow backer is decisive, he'll look faster on the field. Because if a 4.4 guy freezes or hesitates for half of one second, he's now a 4.9 guy.
Confidence and reaction time are, in my opinion, the most underrated traits in football.
The bigger point wasn't to debate Jerry Rice's athleticism, though. It was to say that the WR position is a lot about mastering your craft. Just making the prediction that Harley is going to succeed in a big way. Not saying he's the next Jerry Rice, but I AM saying that he's not so physically limited that he can never be WR1 here at Miami.