&gt;&gt; What were the highly profitable industries built around expert systems and logic computers in the 1980s?<p>I&#x27;m not sure there were any industries built around expert systems, as such, but
don&#x27;t forget that if there&#x27;s a practical application of an AI system, it&#x27;s not
considered AI anymore.<p>Accordingly, expert systems are widely used in the industry today still, first
of all because there&#x27;s tons of legacy software created in the 80&#x27;s and &#x27;90s that
is still lying around and being maintained. But also because the definition of
an expert system is a database of rules encoding expert knowledge about a given
domain and an inference engine to select the appropriate rules in any situation-
and that is exactly what most entreprise applications are that manage business
rules, for instance fraud detection at financial orgs etc (which I&#x27;m familiar
with).<p>And of course there&#x27;s industries where you can&#x27;t afford to use a machine
learning system to do your work. Think of jet engine maintenance for instance.
You don&#x27;t want a system with 10% error doing that. So I&#x27;m told that this is the
kind of job that the industry, even today, leaves up to a good old-fashioned
expert system.