Do NFL teams put way too much importance on combine results?

The players are in track clothes, take a track stance and run 40 yards.    Do this even happen in a football game?

I see dudes in helmets and pads.   They're standing or in three/four point positions.  None are standing like a track star.   There is a football in someone's hands.   Finally, if a lineman is running 40 yards, he's way behind someone else.  Does it matter if he's 30 steps or 32 steps behind them?