Hm, I'm sure you're not doing anything wrong. It's just a slow growing plant. I always expect more leaves but usually just get 3 or 4 leaves total. I treat mine more like a flowering bulb than a big foliage plant, enjoy the flower or flowers, then let it be.
All I can tell you is I virtually ignore mine after I give it a sprinkle of fertilizer in the spring. It's in about a 3 gal. pot in the shade of one of my big oaks, and seems to like a mulch of the oak leaves on top of the potting mix. It's been in the same pot since I got it 4 years ago, except when I rousted it out while it was dormant to get pictures of the bulb. The mama bulb is about 3in. across now. Maybe have a look at yours once it goes dormant? It's got to be building a nice bulb by now.
Yours looks like it has a little darker leaves than mine - does it get some sunlight through the trees? Also, mine's sitting directly on the ground and about the bottom half of the pot is buried in the leaf mulch, too. Maybe this is keeping the pot cooler?
I always wonder when the nursery is charging a lot for a mature plant, if it's because it took quite a while to get to mature size. I shelled out $25 for the mama. Maybe you should just 'park' it somewhere each spring, give it a sprinkle of fert and leave it to its own devices? I don't think it's a fussy plant, just pretty slow growing.
This reminds me, though, I haven't checked mine for any seedlings this year. If I get more seedlings, I'm going to try growing one in the ground directly.
