There was no reason to pay Jaylon at the time. We paid Zeke too earlier, but he cashed in just at the right time. He was the focal point of the offense and not having him out there would inhibit the team. Jerry probably had flashbacks of starting 0-2 as he played hardball with Emmitt.
For Amari he had larger offers on the table and the Cowboys pretty much paid him what the market dictated. I guess they could have traded him or used the franchise tag if they didn't use it on another player. However, hard to fault them after just trading for him.
In regards to Dak these QB contracts are brutal and they did overpay. But what were the realistic alternatives at the time? I do feel they could have played a little harder ball, but think about the Football Team situation with Cousins. He was one of the better QBs they've had in recent years and they're still looking for a replacement.