Locksmith etiquette. I'm unsure if Emily Post described that.
If he made you a key that worked in the ignition, then that key can be used to modify the other cylinders for its successful usage in them, according to the instructions in this thread. If the locksmith were under the impression that you lost a key that worked in all those locks, then it would be reasonable for him to expect that his making one for the ignition would work for all of them; however, old bikes often have replacement parts with locks differently keyed. This thread explains how to make them work with one key.
Buying an ignition switch and key on eBay is unlikely to help your problem but there is an outside chance that the key with the used ignition switch might work in the other locks. There weren't many different key and cylinder combinations, from what I've read. I bought two replacement cylinders for my side cases. They came with keys but my ignition key worked in the locks. :yes
Having a spare ignition switch can be helpful anyway. :2thumbup: