This is due to promotion incentives. There's a much higher chance of getting promoted if you make up something new from scratch, stamp your name all over it and

This is due to promotion incentives. There's a much higher chance of getting promoted if you make up something new from scratch, stamp your name all over it and then during performance review demonstrate how many users it impacted so the committee promotes you. Often times people then move on to another team right after the promotion, rinse and repeat. Even though this issue has been acknowledged internally but the above strategy is still the most promising when it comes to moving up the ladder.