This is the sort of excuses that are simply laughable.
KP was drafted to a team that went 9-7-1 and made the playoffs. A team with a solid WR room. A team with one of the better defenses in the league.
How do you think KP would have looked if he was actually a 'high-caliber' draft pick, and drafted by a true bottom-feeder team like the Bears or the Panthers? There are too many examples of young QB's who have done much more than KP, with much less (Burrow, C.J., Lamar).
Also, almost all QB's picked outside of the top-10 fail. So he is not being 'ruined', he is simply not panning out, which is incredibly common for QB's of his pedigree.