There's a lot to recruiting to be sure.
1. Consistency - If team A's last 4 recruiting classes were ranked #15, #30, #17, #29. And team B's were #21, #20, #19, #20. It's more likely that team B is going to be a better team even though there have been several times where team A gets a higher ranking.
2. Make up - What good is a top #10 recruiting class if half of your recruiting class is TE's and Kickers? What good is landing an elite dual threat QB if you won't let him run? That's obviously a hyperbole, but it proves a point that it depends on what you recruit and how it relates to your roster.
3. Recruiting is a very inexact science - While we might be ranked #13th in the SEC, it's very possible that classes ranked from #8-14 aren't very different from one another. There's a large margin of error.