Why people keep believing that "open trade" solves everything and makes "easy business opportunities"? You can have open trade but also subsidy a portion of yo

Why people keep believing that "open trade" solves everything and makes "easy business opportunities"? You can have open trade but also subsidy a portion of your economy to make that "open trade" not so open anymore. I'm not against it, just saying that a single specific decision makes Dubai and Singapore success is a reductionism that helps in nothing the discussion. Let take OPEC in matters, would you say they follow a "free trade" ideology?