Any plant has a fixed reserve of 'power.' Yes, think of Scottie and his warp engines - Captain, I canna get ya more power to the engines. I'm not a miracle worker; that's the best I can do!
You can maximize the amount of available power to the plant's engines with optimal growing conditions: light, water, fert, air (to both roots and leaves), temp. But at any given moment, whatever you've got is all that you've got.
Your orchids have a choice as to where to spend their energy: root growth, leaf growth, or flower development. Sort of like: warp speed, photon torpedoes, or life support. Under normal growing conditions, you generally get a bit of all three to varying degrees.
But when conditions change markedly ie, a Romulan attack the plant may drastically alter its priorities. Damn it, Jim! I can't tell you what it's thinking - I'm a surgeon; not an orchid psychiatrist! For instance, if you overpot an orchid, where it's roots aren't in contact with the pot wall, the plant will virtually shut down leaf growth and flower spike formation, sometimes for a year or two. It will grow new roots like crazy in the meantime, but it seems to stall above the pot level.
Likewise, some plants aren't strong enough or mature enough to support a large spike with many blooms and they'll tap into their emergency reserves to try and keep the spike going. Cut all power to life support! They'll suck the life out of their leaves, trying to nourish the flowers. We refer to that as the plant suiciding - cut the spike to save the misguided plant!
I'm guessing that with the change in your potting conditions, your plant has focused all its attention on its roots for the time being. That's not bad. Be patient. When the roots are comfortable, leaves and spikes should resume their normal growth habits (and all the more, given a larger, healthier root system to supply more power.) Sort of like a dilithium crystal upgrade!