I don't disagree with that, but the inverse is also true. If a solid majority (let's say 60 percent) were first-round picks, that means 40 percent were not.
So I went ahead and did the look-see. Here's the tab:
59 total super bowls
1st rd pick winners: Joe Namath, Len Dawson, Earl Morrall (2), Bob Griese (2), Terry Bradshaw (4) Jim Plunkett (2), Jim McMahon, Phil Simms, Doug Williams, Troy Aikman (3), John Elway (2), Trent Dilfer, Ben Roethlisberger, Payton Manning (2), Joe Flacco Aaron Rodgers, Eli Manning (2), Patrick Mahomes (3) and Matthew Stafford. So thats 32 of 59. If you include Steve Young (1st overall in USFL, then was a 1st rd supp pick by Tampa from USFL drfatees) it's 33. Then there's Roger Staubach, who would have almost assuredly been a high 1st rd pick the yr he came out had he not had a 5 yr commitment to the Navy. That would be 35.
If you then include 2nd and 3rd rd pick winners you'd add the following: Ken Stabler, Joe Montana (4) Brett Favre, Drew Brees, Russell Wilson and Jelen Hurts. So 44 of the 59 winning QB's would be 1st, 2nd or 3rd rd picks.
The data clearly shows that depending on 3rd day draft picks or UDFA's players is far less likely to generate championships.
Dallas has drafted 1 QB in the 1st, 2nd or 3rd rounds since 1989. I guess it's two if you count the Drew Henson trade (3rd rd pick)