This is interesting.
At my old company there were 3 ways someone could progress.
They could become a people manager (looking after a team of people, making sure their skills developed, looking after departmental budgets, recruitment etc.)
They could become a project manager (running a particular project, being responsible for developing plans, meeting commitments etc)
OR
They could progress up technical grades becoming the local, site, regional, organisational expert in their field.
The impression I have got from here is that the only way to 'progress' in teaching is to become one of the SLT. Maybe there should be more 'progress routes' or something in teaching??
Our company also had performance related pay (having gone off a formulaic system the year I joined in the late 80s).
If your 'worth' to the company was improving (basically you were getting better at your job) you got an above inflation pay rise.
If you were effectively standing still (doing your job but no demonstrable clear improvement) you got an ~inflation pay rise.
If you were underperforming against your current role/pay you got a below inflation pay rise.
I once went to training course in the US from someone well respected in SW engineering. He said that many SW engineers repeated the same experience for 10 years, whereas the good ones got 1 new year's worth of experience each year - they learned and improved.
I could imagine that being the case with teaching. The first 5 years or so you are on a steep learning curve - you get better every year (or quit). But after that I could think that some teachers continue to improve, whereas others maybe plateau and don't really improve. Is that the case?