Richt probably would have made the CFP in 2002, his second season (just like Kirby did). It's impossible to know for sure because the BCS existed in 2002, but Georgia was #4 in the BCS after beating Arkansas for the SEC title that year; they were a 1-loss SEC champ. Surely a 1-loss SEC champ today would be in the CFP. Richt wouldn't have made a playoff in any other year though.
The first 4 years of Kirby and Richt's tenures are remarkably similar, even down to some of the exact losses they've experienced. Especially their 3rd years (see below); they were like a carbon copy of each other. It's eerie, and most Georgia fans are in denial about it.
Year 1: Richt 8-4. Kirby 8-5.
Year 2: Richt 13-1, wins SEC, finishes #3 in country. Kirby 13-2, wins SEC, finishes #2 in country. Both had 1 regular season loss to a big rival (Richt to Florida, Kirby to Auburn).
Year 3: Richt 11-3, wins SEC East but loses in SECCG, finishes #7 in country. Kirby 11-3, wins SEC East but loses in SECCG, finishes #7 in country. Both suffered upset losses on the road to LSU during the regular season.
Year 4: Richt 10-2, fails to win SEC East, finishes #7 in country. Kirby 12-2, wins SEC East but loses in SECCG, likely to finish somewhere around #4/5 in country.
The only notable differences between their first 4 years is that in Year 4 Kirby won a division title while Richt did not. Kirby is 3-1 against Florida while Richt was 1-3 through that same point. I disagree that there's a "clear advantage" for Richt (if anything, I'd give a very slight edge to Kirby given one more East title and a better record against Florida), but their tenures are incredibly similar through the first 4 years.