The Google rankings are misleading because many managers stay on the engineering ladder. (For example, Amit Singhal, who runs all of Search, invented the Google ranking algorithm, and is an ACM Fellow, was a "Distinguished Engineer" when I joined.) Staff through Principal are really management ranks - it's very hard to get to Staff without managing people or being a tech lead on a large project. Distinguished/Fellow is weird - it's split between people who have several hundred people reporting up to them, and engineers who have nobody reporting to them but are allowed to do whatever they want.
I heard one of my PMs say that "Senior SWE" at Google is roughly equivalent to "Director" at Oracle (which also suffers from massive title inflation). He was, I think, the youngest Director at Oracle before he came to Google (he got that title when he was 27).
I was under the impression that to be staff+ you had to be a leader (technical direction) but not a manager (performance reviews, people stuff). How accurate is that?
That's true, but usually being a technical leader of a large project implies managing the people on it, if only because it's good for people to have managers that actually know what their day-to-day accomplishments are. I do know of exceptions. There are a few people who get to staff and even beyond without managing people, but I've heard it's very hard and usually involves TLing a project of the scope of Google Instant (and then you frequently get made a manager afterwards, unless you really strenuously object).
TLing is a completely different skillset from engineering anyway - it's much more interrupt-driven, people-focused, and basically involves being a mentor, teacher, and shit umbrella. When I've TLed projects, I usually find myself spending about 30% of my time coding and 70% communicating with other departments, debugging obscure bugs, managing up, and making sure all the critical parts are covered. Coworkers that are staff+ and TL larger projects usually find it's 0% coding and 100% dealing with politics & coordination.
I heard one of my PMs say that "Senior SWE" at Google is roughly equivalent to "Director" at Oracle (which also suffers from massive title inflation). He was, I think, the youngest Director at Oracle before he came to Google (he got that title when he was 27).