Why would people think it Zeke was only a short term pick for Romo? The Cowboys had clearly established that they wanted a strong running element to their offense, and it's ludicrous to think the Cowboys only thought that was important as long as Romo was the QB. Picking Zeke was simply an indication that they were serious about maintaining a strong running element in their offensive scheme and style.
Teams rarely, if ever, make decisions solely for short term gratification with no concern for how it affects the team long term. Obviously priorities can shift a little depending on how close a team feels it is to winning it all, but it's unlikely the Cowboys or other teams would be willing to completely ignore long term goals with high first round pick.