Valid points, Gary
. As a biologist I doubt that it will ever be possible to build a fully functionable bee substitute.
Sadly, bees are not exactly nature's most perfect invention. They have a shockingly weak immune system which makes it truely surprising that they managed to survive as long as they did. Many pesticides and viruses plus the varroa mite weaken them in addition. In fact, in Germany the honey bee is considered to be on the brink of extinction. Fortunately, we do have a number of wild species of bees, hoverflies and bumble-bees who can substitute them to a certain dregree but these species all live solitary and hence their number wouldn't suffice to replace all honey bees.
Our farmers are most concerned about this situation and afaik there are several reasearch groups attempting to discover ways to rescue the honey bee.
The problem is not all that new: decades ago, several species bees were imported from Africa and South America to be cross-bred with honey bees in order to improove their immune system. Unfortunately, this tactic backfired, resulting in a race of extremely aggressive "killer-bees", not at all suitable for being kept in the vicinity of humans. Personally, I'd count them rather as a B-weapon.