When an employee feels any improvement they make will go unnoticed, they stop. Almost everyone wants a reward for improving someone else’s situation.
Many employees want more money, but more money comes as a by-product of being noticed. Noticing the small changes the employee made that improve the bottom line. It could be better copywriting, more efficient processes, task automation, new customer initiatives, etc.
If the company doesn’t know anything because they are refusing to see what impact employees are making, no employee cares anymore. “Why bother?” becomes the new refrain. Employees become closed off and unaccepting of new methods, eventually they leave.
That’s not to say new employees won’t come in and try to do some new things, but a year or two in, they’ll hit the same wall as the past employees. It doesn’t seem all that big a deal, except short-term employees scratch the surface of changing things. They don’t understand most of the company operations. Long-term employees can make fundamental shifts that greatly change things, but only if companies allow them to, recognize the value of them doing so, and reward the commensurately for it.