Google is a wonderful thing. Leach's average wins per year is 7.7 during a 17 year career. Richt's??? 9.3 over an 18 year career. For comparison, Nick Saban has 10.1 per year (23 years), Jimbo Fisher has 9.9 per year (9 years), and Urban Meyer has 10.76 in 17 years. Dabo has 10.1 over 11 years. Throwing out the 1 hit wonders Gene Chizak and Les Miles, that is all the NC coaches since Pete at USC. Against them Richt is lacking and he has been on the same level playing field with regards to talent, resources, etc .. for most of his career as those 4 guys. Yet, 2 of those guys, with far less years put in than Richt have NC titles.
Does Richt's 1.6 more wins per year make him THAT much better a coach than Leach? I would say no. I would also say that Richt has worked with and been afforded all the talent, bells and whistles, and resources he can amass since day 1 of his head coaching career. Leach is working with far less and ALWAYS has been. At the absolute least, the talent difference, resources, etc ... cancels out that 1.6 average difference. In other words Richt is consistently making 4 star meals with 5 star ingredients and Leach is making 3 star meals with 2 star ingredients at best (since everyone likes the chef analogy's). One of them is doing more with less and it ain't Richt.
Leach might not be a better coach, but I would argue he's at least as good as Richt and it would be fun to see what he could do with Richt's budget, facilities, talent, etc ... His record says he more than likely can't do any worse.