This is completely backwards. It traps highly-skilled, highly-demanded engineers in dead-end jobs that do absolutely nothing to advance the state of the art.
Same with the contractors. SpaceX doesn't use OldSpace subcontractors for very good reasons. They're too slow and too expensive. They famously use industrial grade components rather than aerospace grade components. You can blame the loss of CRS-7 on this practice. OTOH Falcon9 has a perfect record since CRS-7, the highest number of consecutive successes of any rocket ever.