[Jensson]

What makes you think a Principal engineer is tasked with that? Principal engineers do mostly stuff like create new infrastructure technology like spanner, or machine learning frameworks, or similar stuff. Google doesn't have that many principal engineers, they correspond to director on the manager ladder, but there are way fewer principal engineers than directors as it is much harder to climb the contributor ladder than the manager ladder. Most Google products doesn't have a single principal engineer on the team.

[UncleMeat]

Drive almost certainly has an L8 on the team somewhere. It is a big product. And it could be the case that "find a completely new indexing structure that makes drive search and folder navigation 10x faster" is a L8 task. Drive is indeed a lot slower than I'd personally like and a lot of that comes down to the way that indexing works when you cannot group users together, which is at the very core of the product.