The Jones boys SOP is intentional, there is no mistake. It's meant to keep the Cowboys middling to good, with a better chance at being a contender than going 4-12. From a business standpoint that's good. As opposed to the Raiders, 2 winning seasons in the last 19 years, winning 4-5 games every year.
The mistake a lot of people make is thinking they're goal is a championship. That their SOP is with that in mind. It isn't. It's not priority #1. I think this approach is more due to the son. Jerry is a gambler as we've seen. To the point of being reckless. I believe his son has more influence on him now and is the reason for being this conservative.