You know, considering that the L+C world has a man that can fly, clones, time travel, etc., it doesn't seem too off-base for the auto-attendant to have been invented a little earlier. The technology needed to make an auto-attendant work was around for long enough before it existed for it to have been a plausible invention a few years earlier than 1988. I think you should just assume Luthor Technologies came up with it in order to save Luthor from having to hire receptionists for all of his subsidiaries and annoy all of the callers, too (it was probably his idea in the first place).
AmyN
