It's all about talent. Name one current Buff player who would have started for McCartney's 89-94 teams? I can think of maybe 5-6. Miller, Solder, Major, Smith, Kasa (maybe in another year), Clemons (currently unused by our current staff). The rest are backups on McCartney's teams... Heck our backup QB Vance Joseph in 94 was a better athlete than 98% of our current roster.
Let's stick with the facts (from just our 94 team) - Berti, Clavelle, Detmer, Darius Holland, Fauria, Hudson, Irwin, Ted Johnson, Carruth, Greg Jones, Lepsis, Merkerson, Naeole, Rosga, Matt Russell (Butkus), Salaam (Heisman - are you kidding?), Savoy, Kordell Stewart, Westbrook... not to mention Wilbon, Knutson, Troutman, West, Lendon Henry, Kidd, Leomiti etc... I'd say every single one of these players would beat out our current starters in their respective positions... every single one of them... not to mention special teams!
BTW - Joe Paterno went 11-2 last year (at 84 he can still out-recruit CU with or without the help of a high school coach/talk show host/paid spokesperson).