Suppose that under autarky, Colombia makes coffee and cars at \$1 and \$2 each, and Japan makes coffee and cars at \$20 and \$10 each. Since Japan has a comparative advantage in car manufacture, the standard theory says that Colombia will import cars and export coffee.
However, I'm having a hard time imagining how this actually happens in practice. If I run a Colombian car business, why would I import cars from Japan, when they cost five times as much? Why not just buy cars at home?
In general, I see no reason why any business dealing in a single market should care about price ratios; they only see the absolute prices of a single good. For the trade to actually happen in this case, you'd either need a company that trades both cars and coffee (do those actually exist?) or government-controlled trade. Neither of these feel realistic.
If we can look at Ricardo's original example, the same problem appears. Ricardo is assuming that production across an entire country is synchronized in some way; his theory would work if a single business in each country controlled all production of all goods there. But I don't see how the logic holds if there are separate companies producing cloth and wine.
In real life, how are comparative advantages actually exploited?