Whoever someone names as better coach(es) are quickly derided by someone else as not being any good based on whatever basis one chooses to select. It is easy to come up with a list of 10 coaches that probably are "better" coaches than Kelly that would be available to ND but that is impossible to prove.
I've seen Brian Kelly coach for 10 years at ND and it is pretty clear he isn't elite. Kelly is the coach and that is just the way it is. But don't expect the folks who don't bow at the "good enough" altar or accept a 30-3 rout as an "understandable" talent gap to think that there aren't several superior and available coaches ( and I'll leaving out the Saban, Meyer, Dabo and (pick your favorite elite coach who won't ever coach at ND) that would have produced better results with this very team. Are there elite coaches out there? Absolutely! People seem to forget that at one time Urban Meyer (insert Scott Frost or Tom Herman) was just a hot young coach on the come (think it's hard to come up with a list of 10 guys who are viewed similarly now?), Bob Stoops/Jimbo Fisher were no-name offensive coordinators, and Dabo Swinney was a guy with a funny name.
In my opinion, which is as valid or invalid as anyone's, Kelly, after 10 years, with probably a more talented team overall, is producing basically the same results that he did in 2012. We weren't competitive in 2012 and we weren't competitive in 2018. After 10 years, I don't see the progress. Sure 12-1 is a fine season but it was hardly above expectations given the schedule. Again and again, he gets schooled by coaches as not only at "better" football schools but at schools with much lower levels of talent. His teams rarely overachieve and far more often that not underachieve in games. That is a sign of poor coaching, not an under-talented team. Kelly himself said he wasn't out-talented vs Clemson which is either a) blaming the players (something he does early and often as if no other college coaches deal with this problem) and/or b) blaming himself for poor preparation.
The next time Kelly wins a game he "shouldn't," it may be the only 2nd or 3rd time he has done that at ND after 10 years. That wouldn't be true if he were an elite coach.