There are safety ramifications of complacency, and in GA they do show a statistical correlation to flight experience at certain points. But airline safety management systems are pretty good at mitigating that kind of thing. Nobody with thousands of hours in the airlines is going to become less safe as they gain more experience. They might have issues related to the human condition, their personal lives, even perhaps age at some point but not because they flew another 1000 hours over the last three years. That's what being a professional is all about.