That's because there's a clear career ceiling for engineering roles in those companies. They're in a mindset of let's say McDonald's management - there's no career track for cashiers, no "principal burger flipper". They see engineering similarly. It follows from there that the only way to go up is to go to the management.
They're also not the same roles. Usually roles (except fake titles) above senior are a completely different beast just as well. Staff / principal replaces things like architect, system designer and other positions we had in the past.
Alternatively, I've seen a "senior principal" dev working effectively as IC in a technically very demanding project (specialized database engine).
Basically champion firefighter in addition to what you describe. Arguably the role we'd have if there were many CTOs and they were still practicing, instead of getting showtime
You end up doing less coding, more mentoring, drawing diagrams or doing requirements analysis with the team output customers.
I never get why companies are so fixated on salaries being tied to titles. People just do different jobs and you shouldn't need technical or people leadership to get paid more.
If someone is really effective at their job they don't need to be called (or do the work of) a principal engineer. Just pay the 10x engineer 10x.
That's on a company's performance reviews... and so how do you measure salary increases, bonuses, anything? There shouldn't be a different standard to it.
The only difference is the engineer shouldn't be forced into a different field to get paid more.
> What’s a 10x engineer
It's just an expression I'd say. Can be 2x, 5x, whatever. Most of the time a good engineer is forced into management of some sort (technical or people) before the 2x mark (salary wise).
More frustratingly, for example quasi-governmental places, the total comp raise any individual can receive is a hard limit written in their rules. Even if you skipped 5 levels you couldn't even get that raise. That's why new employees are hired at a higher rate than existing employees. The only solution is to quit for a time and then come back to the org. Though maybe once every 5 years they'll do a realignment of pay bands.
If only we do the "same" work and provide the "same" value in software. 90% of the time you're always doing something different and hence why estimates fail.
Someone that knows the ins and outs of an ever complex system will be worth the 30-40% bump. If it was so simple there would be a lot less stories about rewrites etc, which often occur because no 1 knows and maintained the existing system.
Knowing how an entire large or complicated product works can be very important, and can take an immense amount of time.
In fact, most engineering jobs that I've worked existed entirely because shoddy and poorly engineered products needed whole new product categories invented to make up for shortcomings.