Those miniature phalaenopsis orchids (Phalaenopsis) with tiny flowers that are sold everywhere these days are not cute little babies in early bloom. Any orchid in flower is fully mature or it wouldn’t be flowering. They truly are genetic miniatures, the chihuahuas of the orchid world, and won’t get much bigger over time.
If you like small orchids with small flowers, go ahead and buy one. If you prefer bigger orchids with big flowers, buy one of those.
In the home, no phalaenopsis bought in bloom will increase too notably in size (unless you let it divide into two or more plants and that can take decades!) Most will just produce a new leaf for every old one they lose, maybe over time adding at most one or two more leaves to their total. That’s just the way they grow. Get used to it.
Sometimes what you see truly is what you get!