I have no idea why anyone would want to draft a running back in the first round? In today's NFL you want longevity with your first pick and drafting a running back isn't it. It's very rare that an NFL running back is going to have the same impact and effectiveness during his second contract (if he even gets one) like he did in his first. There are so many better options there so if the Cowboys were smart in the first round (they've done very well here btw) they will pass on Bijan Robinson, who is a very good running back but the Cowboys will do so much better in the long run with an offensive lineman. Connor McGovern's spot hasn't been filled so an O-line at 26 would make a lot of sense, especially with all the good O-lineman that they've drafted in the past in the first round then maybe take a running back on day two or three.
Only fools draft worrying about a second contract in a league with 20-30% roster turnover every year.
Show me how many backfields are intact five years later? Easy to answer: NONE
Now one could say QB is an exception but is it? QB is the biggest gamble of all as history has proven. Besides, if he does turn out to be the guy what does it matter? You will end up paying whatever it takes to keep him.
Now as regards RB it certainly can be argued that they have a shorter service life at the top of their game then probably any other position.
THEREFORE worrying about a second contract THERE is idiotic.
IF you want to keep him an extra year then you franchise him. Even two years if it comes to that.
Now if you are arguing, as you seem to be, that a short career is a reason to not draft anyone at a position, I ask you why?
In case you have not noticed it, the average career in the NFL is LESS THAN FIVE YEARS.
In case you have not noticed it a team with a few exceptions has at best 5 years before it has to be rebuilt.