It's not "random."
It's called, gee, let's look at all the best QBs. Here is a stat that they have in common: They all pass for like 240, 250, 260 ypg or more.
Now lets look at all the replacement level QBs, the Alex Smiths, the Tyrod Taylors, etc. Here is a stat they all have in common: They generally don't pass for like 240, 250 ypg. More like 220-230.
Now let's look at all the loser QBs who get drummed out of the league, the Tim Tebows and Colin Kaepernicks and Quincy Carters. Here is a stat they all have in common: Their ypg hovers around 200 or less.
Uh oh. Where is Dak Prescott falling on all this?
I'm being random, though.
But oh, Jared Goff didn't light the world on fire as a rookie. Yeah, no shit, it's called.... he was a rookie. By time these guys are in their 3rd, 4th, 5th years, they have generally ascended to better than 220 ypg, when they are in their primes.
Dak is regressing.