I would think that about 20-30% are “senior”. I worked at AWS for 3.5 years until last year. I would assume the distribution is about the same thing for most other tech companies.
Doing a quick bit of research, you’re not to far off. My back of the envelop math is about 7.5% work at FAANG + Microsoft. Maybe 10% if you include other companies that pay in that range
I think your assumption is way off. From what I've gathered, each team typically has a single L6 engineer (some have zero), and each independent organization has a single L7 engineer. We're talking one senior engineer per 9-12 engineers, one principal per around 50 engineers.
Senior engineers tend to have a 1:1 correspondence with software development managers, whereas principal engineers have a 1:1 correspondence with senior managers.
> I would think that about 20-30% are “senior”.
You should check your notes, as they are way off. Even if you Google the topic you get 15% senior engineer, 2% principal engineers. I know for a fact that flagship organizations within Amazon have a single principal engineer, 4 or 5 senior engineers, and around 50 L4-L5.
L6s are tasked with interfacing with higher-ups, such as product owners and senior managements. They coordinate with principal engineers to design and deliver critical features. They help communicate and coordinate tasks with SDMs about the work that other SDEs need to do to reach goals.
By design, they are normally one senior SDE per team, and a single principal engineer per organization. They are there so that senior managers and executives can discuss plans, goals, and roadmaps. You definitely do not need a team full of interfaces.