When I joined Google my TL was an L6 on the engineering track, 10 years ago. My vague memory of the engineering ladder when I joined went up to L9.
- Organizations are very bad at promoting
- Retroactive pay scale adjustments are rare
- Promotion requires tenure and often companies don't align incentives towards tenure
With that usage, the point at which the company stops being "up or out", it was L5 when I joined, and L4 when I left.