Bulbs are hard to grow and there are so many things involved in their success and failure, according to my understanding the bulbs fail to grow because they were not in soil (planted) at the right time and the reason was the time of our purchase was a bit late and then they skipped the cycle and went into dormancy again and bulbs are not like seeds they cant be kept for longer, like Scillia in current purchase are sprouting already even though they were not planted because if their clock tell them to break the dormancy and start growing they grow in most cases and in some cases if not like Glads even then they will die and will not sprout next season because they behave different as compare to seeds, seeds can be kept for longer but bulbs 99.99% will die and that was the case in 1st purchase but this purchase will behave different because this is the right time to plant them and hope you will get better results.
For the same reason you cant buy off season bulbs but you may get off season seeds, most of the suppliers put the bulbs on sale at the end of the season because they cant keep them for the next time and they prefer to sell them at any price they can get considering something is better then nothing.
Tip to keep bulbs for the next season if purchased at the end of the season
according to International bulbs society if you purchase something (Bulbs) at the end of the season don't keep them for the next time its always better to plant them and let them grow to complete the cycle, they may not flower or perform and then you can dig them up and store them for the next season, in this way the casualty rate will be very low and you will still have something for the next season instead.
My experience
I have first-hand experience with Glads, once I bought Glads on an offer (quite cheap) and plant them in August, they were not looking good and shrinking already but I took the chance and planted them and all sprouted and couple of them flowered and I manage to save half of them and that was in Pakistan Wah Cantt.
the above conclusion was according to the situation but the reason could be many more as I have said earlier there could be many factors involved in the failure and success of a bulb as they are too complex to understand, but we are not giving up and getting there with the experience and experiments

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I hope this will help
Hamad