I don’t think you have the history here.

Technological development - decent ships, actually good and reliable navigation, and knowledge of exploitable opportunities (sugar markets, and later cotton).

Energy gradient - cheap labor (in the form of slaves) in Africa, cheap arable land (Caribbean, US, South America), hungry markets with excess wealth in Europe.

First, the Caribbean got exploited (with open markets!) rather brutally, until the slave rebellions starting in 1790, and further escalating.

Haiti in particular, won their rebellion - and then were completely economically isolated (by closing the market!) by the European powers. They still have not recovered economically, same for most of the Caribbean.

Around this time is when the US markets (less ideal to exploitation, but larger and more controllable) in both sugar cane and cotton started to take off using the same sources.

Which fueled significant tension between the northern states (no crops easily amenable to slavery, rather being capital manufacturing, livestock, and secondary goods like weaving/textiles) and the southern states (many labor intensive crops, amenable to slavery).

Attempts at controlling the open markets in these crops by dissimilar interests (by either banning slavery or by blockade) is what led to the civil war.

The south couldn’t ban slavery without bankrupting their economy. The north couldn’t allow free trade/slavery continue without making themselves less competitive, as Europe has more developed textile mills and heavy manufacturing. So them getting the goods directly was undercutting northern US competitiveness.

Notably, the British, being the first into the Industrial Revolution and the furthest along, were also the first major European power to not just ban slavery in their country - but all their colonies, and everywhere else they could reach.

To cut off the ‘energy gradient’ of cheap labor, and make their products (more capital intensive manufacturing) more competitive.

The Caribbean is poor because they rebelled against exploitation, but couldn’t capture the economic engine that was exploiting them - they got bypassed by a competitor.

And by the time their competitor (US Deep South) also got broken, the underlying energy gradient that led to them being exploited at all was cut off.

So all they had left was ruins, debt, and disease.

Sucks to be them.

So, depending on how you measure ‘good’, they’d have probably been a whole lot better off with a closed market that would never have let the initial energy gradient be formed to begin with, eh? Or at least not allowed the extremely rapid and rapacious exploitation.

Think of open markets as a full open floodgate, and closed ones as having a valve at various degrees of closed off.

Flooding is very ‘profitable’ if you can somehow harness it (very difficult to do), but can be very unpleasant and destructive for those caught in its path. It’s nearly impossible to die of thirst in a flood.

Restrictive flow doesn’t product as much ‘profit’ but has the potential to produce more desirable outcomes if used effectively. As long as the dam doesn’t burst of course. If the valve is misused or turned off, it’s easy for some (or even all) to die of thirst.

Pick your poison.