Except that working on stuff for FAANG doesn't necessarily make things better and instead just helps with monetization and/or lock-in.
Is it really an improvement to cover more of the search results page in ads, centralize ever more functionality on that page which pushes out smaller/independent competitors, track users more comprehensively and optimize mobile loading times by creating a corporate-controlled, Google-hosted format that companies are coerced into instead of doing the same thing with standards-based, distributed technologies?
Is it really an improvement to the "web stack" if Chromium kills diversity in the browser engine space, blurs the lines between client software and Google account, then proceeds to limit ad-blockers' capabilities via extension API changes? While at the same time Google web sites happily go about cross-advertising for more monoculture and deliberately not supporting Firefox even where it provides all required functionality.
(Similar examples exist for other market-dominating companies and products.)
One man's improvement is another one's trading the long-term health of tech and business ecosystems for short-term convenience and stock market returns. It's tempting to believe in the usefulness of one's work is when the massive scale and complexity of FAANG companies make it so easy to miss the forest for the trees.