No, the issue is that the incentives are wrong (features, features, features for promotion) and indeed the engineers (on average) are not that talented.

Citation needed. I never see the same level of dedication in big Google or Facebook projects as in well run smaller projects like SQLite.

You are directly rewarded for "new" features (i.e. plagiarizing or rewriting old ones and selling them as new).

So I don't think the engineers are particularly talented, and the incentives are not the same as for SQLite.

If using Rust results in fewer bugs for less money, shouldn't we still do it?

The reason SQLite can test so thoroughly is that their requirements never change. I have tried to browse the web with SQLite but so far no luck.