this may be true but it's also important to remember that we're recruiting to win college football games not NFL games. a lot of these diamond in the rough guys were late bloomers, or hyper-athletic raw prospects who needed a half-decade of playing quarterback to get to an elite level. there are some college studs underlined here (Lamar, Russell, Matt Ryan) but also a number of guys who played their best football in the NFL. the college careers of Watson, Burrow, Murray, Stafford, Hurts are far better than Allen, Mahomes, Rodgers, Brady etc -- the first group has multiple national titles, Heismans etc. some part of that is obviously not the fault of the second group (bad coaching, middling programs) but the 4 and 5 star studs give you the best chance of getting a superstar college player who can carry it into the pros. Mac Jones is the only one who was an unheralded QB recruit who played for a championship team in college and was deemed talented enough to be drafted in round 1.
the best argument for Emory Williams is that QB recruiting is just incredibly volatile. it's true that Bama, Georgia, Ohio State stack chips at QB. they've also ended up starting Mac Jones, Stetson Bennett, and Justin Fields (transfer) in recent years -- and Georgia tried to take a transfer. if you get your roster to that level you can develop lesser talent as useful stop gaps and not have to rush young QBs, and/or can attract superstar transfers (Burrow etc).