That matches my observation in the 90s: people working at customer sites were less likely to get promoted than their colleagues working for
the same boss in the headquarters. The best it could happen to them was to become the manager of the other our people working for that customer, but always there. If you're good the customer asks explicitly for you and you career stops there. The paycheck might be good though. If you're not good, you stay there unless you're a total disaster.
It depends on what you are good at. If you are good at your day-to-day job, yes, you stagnate there. If you are good at helping junior teams members learn and grow and become as good as you at the day-to-day job, you get promoted.
That doesn't mean that lower visibility to your management doesn't have an effect - it clearly does. But there us more to it than that, as being remote also makes it harder to mentor others. It can be done... it is just harder.
