There are a number of reasons a hen will be reluctant to jump down from the perch. I currently have four hens of advanced years who wait for me to lift them down from their perch which is less than three feet high.
The reason the oldest hen, a five-year old Brahma, doesn't like to hop down is that she's heavy and it hurts her feet. I try to keep plenty of bedding under the perch, but she learned years ago to fear jumping down. The others are also getting old and may not see as well as they need to. Also, the coop is narrow, and I've seen them misjudge and hit the opposite wall, which is a window. So they wait to be lifted down rather than risk crashing.
Check your hen's feet to see if she has any swelling or bruising. If the floor is hard, that may be the problem. It could be simply she lacks self confidence and doesn't believe she can do it. If it's no trouble, just keep lifting her down. There's no shame in it.