The reason Jones fell is that he was a marginally athletic talent who was older coming out of college and had a lot of technical issues. The idea was that if you could get him right, he could be a starting caliber player. The Cardinals obviously did not see enough growth to prevent them from extending Beachum, signing Winters, and then starting Jones over Murray and Winters.
Also we have to remember Dj Humphries went and spent multiple offseasons at LeCharles Bentley's OL academy to improve. At this point, we do not know if Jonses is doing anything additional or not.