During his early years in the Kremlin, President Vladimir V. Putin used the annual economic conference in St. Petersburg as a marquee event to showcase how Russia was becoming a magnet for Western businesses.

Multibillion-dollar oil and gas deals were signed, including the agreement to build the Nord Stream 2 pipeline between Russia and Germany. Western corporate giants such as BP, Chevron, Deutsche Bank and Total sent their chief executives. In 2018, President Emmanuel Macron of France was the guest of honor. In 2011, Sting performed in front of the Winter Palace.

But the event, which opened on Wednesday and will run through Saturday, now reflects a Russia fundamentally transformed by Mr. Putin’s invasion of Ukraine in 2022.

The Kingdom of Bahrain was the guest of honor, and the Chinese brand Tank, not Mercedes, was selected as the official car. Instead of executives from Morgan Stanley and Citibank, a delegation of the Taliban roamed the giant exhibition center. And only second-tier Russian pop and rock stars were on show, with no international acts appearing at all.

The conference’s message is that Russia will never again be so reliant on business with the West.

Despite newly opened lines of communication between Mr. Putin and President Trump, major American investors once again shunned the conference. The Russia-United States session, billed as dedicated to “identifying shared interests and shaping long-term partnerships,” was open by invitation only.