Cinta, tell me about your (non-blooming) plumeria. What are they (if named), how tall, are they branched, and what are the size pots. How often do you re-pot (up-pot)? Are they now "deceased"?
What are your growing conditions for your houseplants and what houseplants do you grow? I assume the only orchids you purchase are those "moth-orchids" found in big-box stores. If you have tried another genera than Phalaenopsis, what genera have you tried?