You know, I mentioned that the thread came back into focus because of the economic and infrastructure issues that have been in the US news lately, but I want to also point out the language of the OP as how it relates to a pernicious (IMHO) idea that is common. Note this quote is the whole of the OP, from Feb 2023.
Granted, in non-representative governments, there’s not a lot of chance for those not already in a position of some power to push for change, but it reminds me a bit of our ongoing discussion of how the DOJ isn’t saving us from Trump.
[ and no, before you rightfully toss a bunch of bricks at me, I fully agree that asking people to pull themselves up by the bootstraps, “man up”, or “work harder” is unspeakably unfair and ignorant of all the constraints legal, cultural, and economically imposed upon them ]
But, in general (oversimplifying) those who are already in a position of leadership, in Cuba and around the world, are so heavily insulated from the lack of prosperity that they have minimal reason to improve the general lot as long as their power isn’t at risk. In a representative government, sure, there’s the chance that sufficient misery can push out the vote, but even there, as our current USA situation shows, you can always push the blame, rightly or wrongly onto someone else. And we, and the rest of humanity, fall for it in disturbing percentages throughout history.
So, taking things back a step, asking existing leaders to lead the way to a “prosperous” Cuba is probably a non-starter.
Which brings us back to most of the recent discussion in the thread. Does Cuba need a change of government, whether representative or other, or international partnerships to prosper?
Probably IMHO. If the situation is as bad as reporting leads us to believe, alongside multiple hurricanes and tropical storms, with said storms becoming the expected new normal in our current climate, something has to give. Not always for the better, but again, the thread is prospering.
If this had been, say, before Covid and all the resulting issues, I’d have expected China to step in and provide help in exchange for power and influence in our backyard (no, I’m not the first, even in thread, to suggest this). After all, China is a world leader in the theory of prosperity =/= freedom and democracy. But since their current stability is based on the two concepts of strong central control and economic prosperity to quiet discontent, they’re a bit busy and internally invested right now.
So, back to the OP’s question. What will it take to allow Cuba to prosper. If it’s too far gone (for all the reason I and everyone else have mentioned) to save itself, then it’s going to take the international situation to grow divided enough that the local basing (from China, Russia, or other polity wanting to cause caution in America) is sufficient incentive to cause investment, or for the world situation to become good enough that other nation-states with to be seen as benevolent in their generosity to secure international approval.
Guess which of the two scenarios the world seems headed towards. 
The “good” news for the rest of the world, and the bad news for Cuba is right now, none of those powers that would benefit from the first of those two scenarios seem to have the time, energy, or money to bother when they have much more pressing concerns.
As for the USA helping out, even if there were major Democratic reforms, between MAGA (right there in the name) putting the emphasis on internal “enemies” and Democrats rightly pointing out all of our other commitments, and fighting off a misinformation war on how we’re “wasting” money on non-citizens out of compassion and a realpolitik need to keep expansionist militarist nation states cautious… no, I don’t see much help there either.
Idle IMHO thought though, I wonder if all the middle Eastern Petro-States would be better served investing in Cuba and other such struggling nations, rather than throw more money at things like LIV golf, or building another mega-structure. Absolutely more risk, granted, but…