You can call it a psychological problem if you want but calling names is not a solution, nor does it really provide a good path to finding a solution. The labor market being what it is, people will leave steady jobs with good pay for more exciting work with riskier prospects and less pay. This happens all the time.

Bug fixes and incremental features will generally not get you promoted for good reasons, we expect senior engineers to have system design skills and there is simply no way to demonstrate that without having your engineers design systems. If you only assign tasks based on the needs of your product and not on the needs of your workforce you could easily find yourself with a critical skill shortage.

There's a certain inefficiency to this, but only if you put your blinders on. If you have engineers churning out meaningless work then you certainly need to address that problem, but if you prioritize short-term product success over team health you are only trading one problem for another.