Some years, if the bulb doesn't have enough room to grow in a pot or doesn't receive enough nutrients, it will produce only leaves to stock up energy for blooming the year after.
I'm not sure what area/ climate you live in, but I think 1) that your bulb is just naturally preparing to enter winter dormancy, or 2) if your area is in spring, it may be producing just leaves this year :( coz flowers usually appear before leaves. But if you are patient, fertilize it when in leaf/ growing, next year it may have more/ bigger blooms.
hope this helps a bit
I was given an Amaryllis as a gift a year ago. It grew from the bulb pretty fast and looked really good. Then the tips started to yellow and all but one wilted away.
I just moved it to a bigger pot, it has a big root system but only one long leaf (not sure thats what its called but anyway). Is there a way for me to get it to grow more leaves? It looks half dead with just one.