Phalaenopsis - All roots - No flowers

I have two phalaenopsis orchids which both flowered about two years ago.

After the stems went brown, I cut them off at the bottom above the leaves.

I am getting big new leaves on both and on one the new roots are quite a short length and now this is growing a flower stem, but the other, larger one, is growing a large number of very long roots, but is not showing any signs of growing a flower stem.

They have both been treated the same, with orchid food and light spraying. They are sitting on trays of large gravel which is kept damp, and are in dappled light.

I also have a Stephanotis with the same non-flowering problem.

Any ideas please.