When I bought my "tiny" Asiatic lilies each stalk had at least 4 flower buds on them. Now they are only producing one on each. Is this normal?
It could be related to soil or light conditions. For example, you bought them (let's say last year) and they were from the nursery, looking all big and healthy.
Then this year, they grew their stalks but only ended up with one flower. It could be the growing conditions, which include the soil, light, water, fertilizers, ,etc
This is a common occurrence. Check light, soil, and water conditions.