Not really. Other countries with "regular capitalist economies" if there is such a thing have been scared shitless of an embargo and every single one has seen economic disaster.
The key to the embargo are two measures, the exclusion of Cuba from the global financial system, and the restriction on ships that docked in Cuba. Because of these, trade with Cuba from other countries is severely restricted.
It's the same situation as the Iranian embargo, just even worse. As you can see in Iran even in capitalist countries it causes untold economic disruption.
There would 1000% be a blockade even if Cuba became capitalist as long as it was opposed to US geopolitical interests. The US trades with endless murderous dictators and even traded with the USSR, the determining factor of the embargo is the Monroe doctrine, not anything else. Ever since 1776 Cuba has been struggling with escaping the American sphere of influence.