Yep, I assumed wrong. Thanks to everyone who pointed that out
I guess the point that would be up for question is the way they calculate the payoffs. But it's very interesting, and very in-depth. Thanks for sharing the links.
I did think it's mostly to do with pressure that they don't do it. Everyone will think the coach is crazy and demand they get fired on the occasions when it doesn't work.
One thing to take into account with the onside kick recovery statistics is that onside kicks are likely not a focus of practice for teams that are only going to be doing them maybe once every 4 games (if that). If a team decided to never punt then they would spend all of their punt-practice time practicing onside kicks instead and they would become much better at it and that percentage would increase.
I coach here in Nebraska and I am of the opinion that if its 4th and 3 or shorter I am gunna go for it every time beyond my own 35. If you demand to your players that we need 3.5 yards per play at the minimum, and then you instill that thought into them. When its 4th down and 3 and you punt. That tells them they you know they can't get the job done. Thats my opinion though and I'm hardly an expert. Just my philosophy