There is a ceiling to how much value you can add vs someone that is not getting a 30-40% bump. Your salary is going to be a formula based on the value you add to the company and their ability to find someone else to do that work for less. There are a lot of factors of course but the gist of it is if you keep doing the same work and providing the same value increasing a salary by a large percentage just doesn't make sense.
There isn't really a ceiling to great engineers, I'm not sure how you came to this conclusion. As an engineer, your knowledge base constantly expands, and building a well engineered system can make a product far better for far cheaper.
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.
> There are a lot of factors of course but the gist of it is if you keep doing the same work and providing the same value
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.
