For one your prospects are tied to how well your project does. Sounds reasonable right? But what this results in is many teams battling to "win" with politics often playing a large role in who is the victor, rewrites of existing code essentially to prove your technical prowess and make your promotion case and little to no valuation of team value rather than individual value, namely that teams are (or can be) greater than their sum of parts.
The last point is a key one and an area where the likes of Damore go wrong. The best team isn't one simply that's the sum of the people who individually had the highest "merit".
Put another way the cynical view is your shit never breaks no one notices but if it breaks in a big way and you fix it, well that's impact. Likewise adding a feature isn't nearly as much impact as rewriting the whole thing from scratch.