My oldest orchid was a gift many years ago, it blooms every year and brings out new leaves every year, they are flexible and can be bent without any feeling of it being brittle etc, everything about it seems fine, other than the simple fact the leaves look very unorchid like!!! (The picture shows the plant plus a leaf from another orchid for easy comparison)
Obvious answer is that it needs more light... but as everything else about it seems decent is it possible that some orchids just have darker leaves?