Jerry is a shrewd businessman. I don't mean he always strikes the best contract deals, but he certainly knows how to market the brand and generate value.
He is also supremely good at keeping the Cowboys topical and relevant in the media. You have to admit, for a team that hasn't really challenged for a SB in 30 years, the Cowboys are likely the most cussed and discussed team in sports.
This is why I think he seemingly drags contract discussions along for such a long time... it keeps the Cowboys front and center in the news.
Whether Dak is signed or not, it generates intrinsic value to Jones and the Cowboys. No matter what he does with the Dak contract, there will be an equal number of "love it" and "hate it" fans. He really doesn't lose (financially) either way.