The fall of Constantinople was important historically. Economically it was about as inconsequential as can be imagined.
Constantinople for more than a century before its fall was only a minor city-state, surrounded and totally overshadowed by the Ottoman Empire, of which it was a vassal.
Western Europe had been cut off from the Orient for many centuries by Muslim states: Turkish, Mamluk, Fatimid. It was the policies of those states with regard to trade that affected spice prices in Europe. Frequently they got stupidly greedy and raised prices to the point that they strangled trade.
“Economically it was about as inconsequential as can be imagined.”
Trabizond was the second largest trading city in the mediterranean. I’ll give you one guess as to the first.
Sure, they were much less powerful than they had been before, but still, they were an incredible prize.