Microsoft also heavily relies on contractors, which according to law says if you hold a contractor for longer than 18 months they deserve benefits. So Microsoft has a whole system of contractors who after 18 months are promptly let go, and then in 3 years can reapply.

343/Halo devs gave reported they have lost wildly talented devs because of this, and many pount at least half the blame of Infinite squarely at this. (Contractors are mandated my Microsoft)

Microsoft hugely believes everyone is a cog and easily replaceable.