Power 5 kickers / kicking has always been an enigma for me... It's like there are 64ish spots for kick off & FG/PAT. With the number of high school boys in the USA you'd think every single P5 team could have an excellent kicker every single year. My HS team used a kid from the soccer team. He did three things all practice; practiced kick-offs, FGs, and PATs.
Why aren't they all great?
I think there are a few reasons that they aren't all "great".
First it is a mental game - more so than just about any other part of the game. You have just a few chances to execute every game and you must execute flawlessly every time to be successful.
In addition you can be perfect from 30 yards then the expectation is that you push that range out to 40 yards. If you can hit from 40 you should be able to push out to 50. Once you hit 50 then 55 should be expected, and so on. You have to perform every time at the very fringe of your abilities.
And none of this takes into account bad snaps, bad holds, bad footing, swirling winds and angry 200-350 lb. men trying to break your concentration or worse.