The Bills put Josh Allen into a massively shit situation when they drafted him. It was probably the most talent devoid offense an NFL team has put out.
He had no oline and no skilled players.
On the line were two starting linemen that were out of the league the next year including the center, two of the others lasted another 1-2 yrs as backups and the best player on the line was a rookie Dawkins.
At skilled positions, Kelvin Benjamin was his first option and he was out of the league after the season along with basically every other receiver. They had Zay Jones too but he was a mess and had a manic Spice/PCP incident around his rookie year and they ended up getting rid of him 2.5 years into his tenure. And 30yr old Shady had completely fallen off that year
Baker was given adequate talent around him so I don’t think the Browns did more than the Bills in terms of roster building specifically offensively. Defensively is a different story.
And coaching never interfered too much with Allen’s development. Allen accredits most of his development on private coaching in the offseason with Jordan Palmer and a biomechanics lab
Everyone was down on the big tall project qbs because of guys like Paxton Lynch and Osweiler.
And the league at the time was dominated by pocket passer game tacticians in the twilights of their careers (Brady, Brees, Ben, Rivers, and even guys like Matty Ice to some extent). The new game manager pocket passers were killing it too with Goff looking great with McVay in LA.
QB’s like Allen, Mahomes, and Lamar were so counter culture to what people considered a successful looking QB.
Fans wanted traditional pocket passer / supposed high IQ build which Rosen fit