When Barron’s gathers some of Wall Street’s best minds—as we do every January for our annual Roundtable—we expect some consensus, some disagreement, and one or two off-the-wall notions that sometimes turn out to be surprisingly prescient. This year did not disappoint.

Investors entered 2020 with the financial markets heading higher and a lot of optimism about the economy. Then the latest flare-up in the long conflict with Iran reminded everyone of the many geopolitical risks lurking under the seemingly placid surface of the...