Maybe I misinterpreted, but it sounds like you deify L6 engineers as "better" and that's why they remain. I don't think that's exactly it lol.
Also..people leaving in 2 years as L4/5s aren't "failing fast." They're bailing for better gigs with a few Amazon projects on their resume - I'd even go as far as to say that's many of their plans coming in!
I agree with you on Amazon not being so bad. I had a lot of autonomy and was asked to both be an engineer and build technical solutions and own processes end-to-end (which included some project management.) It was a great experience!
Nice guy that referred you! Not everyone is that open, usually people learn it the hard way.
That’s a good point that some people leave by plan. On the other hands there are tons of L4/5s get into “PIP” within a year or less and generally we know Amazon holds a lower bar at interviewing, that’s why I think it “fail fast”