Romo's 8th year as starter was first year with real OL and that was with rookies for most part. by that time, you could see the wear in his body/play. It was too late for this team and Romo. It would be unfair to compare the benefits of Romo's last 5 years to Daks first 8 years (so far) especially when all aspects of this team and its talent level has been so much better for last several when compared to all of Romos career.
I am not bashing Dak. I think he can do something with this team, but yeah he needs to work on consistancy, his ability to see the open receivers, and speed at doing so.