The three are not interchangeable and they fix different problems. A blunt guide to which instrument fits which stall — including the cases where the honest answer is that you need none of them.
The skill that got you hired as a PM is not the skill that keeps you booked. What actually changes when you go independent, how the first three clients arrive, and the honest case for not doing it.
Most PM ladders describe responsibilities. The real difference between levels is what kind of ambiguity you're trusted to absorb — and which of the three hard transitions you're standing in front of.
The gap between PM and senior PM isn't output — it's evidence of judgement. The four artefacts a promotion committee is actually looking for, and how to build them in two quarters.
The questions that actually get asked in PM interviews, grouped by the skill they probe, with the difference between a weak and a strong answer — written from the side of the table that does the hiring.