This is just a ridiculous excuse to draft a RB because you want one. No one picks in the top 4 of the draft thinking, well I just want him for 5 years because we will rebuild again by then. If you're rebuilding that often you'd have to get like 5 starters every draft just to be successful in the NFL.
1st round RB's who aren't busts are usually elite for about 6-8 years, not 5 like you are suggesting. Who are you thinking of (that wasn't a bust)?
In general when you draft you are shooting for the next 5-8 years, so if it's just the first round we're talking 7-9 years. That by definition ensures a second contract since rookie contract lengths can't be longer than 5 years.
Most draftees will be quality depth and never start.
You need your 1st and 2nd rounders to start, but expecting them to have careers more than double the NFL average is more than stupid, it's delusional.
DeMarcus Ware and Terence Newman were 9 year vets who tailed off in their last year. Mario Williams played with his first team 6 years. Logan Mankins also lasted 9 years and the great Richard Seymour was traded away after 8 years.
Rare HOF caliber players like Ray Lewis and Brian Urlacher have long careers, but they are indeed very rare. If you are expecting an Urlacher from the 4th pick, again you're kind of deranged. Not going to happen.
Who's drafted that high besides a QB or maybe an OL that you actually plan on being a backbone player 9 years from now?
Be realistic.