I don't think it's a myth. Example, the NY Giants had a number of good linebackers in 1981. They had Carson, Kelly, Hunt, and Van Pelt. All legit NFL guys. There was, however, a clear BPA at number 2 in the draft. The Giants needed just about everything else other than LB. They were pretty bad. OK, maybe they didn't need a QB as Simms was still very young. You know who they picked and it was the correct pick. They repeated that several years later with Carl Banks and then again with Pepper Johnson. I'm sure there are plenty of quotes from teams that have selected guys based on a list of prospects that presumably ranks how good they are? I recall Fitz being quoted to that effect when Mukhamadullin was picked? I'm sure there are instances where a team selects from a tier of similarly ranked guys to go with need as a tie breaker but I'm skeptical that a team will avoid a clearly better player to pick a clearly worse player just based on position.