That'd be great, but even if Pedro Castillo wasn't arrested, or "Correists" gain back Ecuador, it doesn't seem like Cuba's or Venezuela's struggles for their right to freely choose socialism would be resolved either way(, for their own good, of course)(, i would not deny some improvements though, even if their power is limited).
Capitalists-owned countries would perhaps accept to be united with socialists, but also atheists with theocrats, republicans with royalists, socialists with so-called "anarcho"-capitalists, so-called "liberals" with so-called "illiberals", or anti-populists with direct democracies, if they didn't fear in each case some kind of contamination inside their borders, it may be the number one reason for all these wars waged against leftist ideals and "othernesses" in general.
If that's indeed the main reason preventing a union throughout the world, then finding a solution to this problem may be important.

You didn't asked, but i can see two categories for this problem :

• Western governments and others could perhaps accept to unite with other ideologies if everyone agrees upon a status quo ensuring that no "contamination" will ever occur, the problem being that it's unrealistic&undesirable to ask for all evolutions to cease, populations should be able to switch sides or create new ones if they want to. Such refusal will imply more wars of influence to spread our own ideology over a uniform world ;
• Western governments and others trust their ability to keep control by force, and/or to convince their population that their ideology is better than the foreign propaganda they'll inevitably be exposed to, especially in the case of a united world in which every country is helping each other. The problem being that capitalists are aware that a lot of people are stolen from in order for a few to be wealthy, but they consider that it's the best system, and that you unfortunately can't trust the exploited to see things their way, so they will never agree to this solution, unable to win the debate ;
• In between these two options, there's the possibility for countries to be promised the first option of a status quo, in order to trap them in a world union, but throughout the century progressively switch to the second one of a possible "contamination", as progressively/insidiously/legally as possible. That's dishonest and a reason why even this first option of allowing a country to leave in a bubble wouldn't be trusted by them, but the only one i would bet on based on my current humble understanding.
  The best option would ideally be that westerners were convinced their propaganda will forever be more powerful than the socialist one, that they have nothing to fear, but that doesn't seem realistic either.
  It truly seems to me for the past few days that this question is an important obstacle towards understanding how we could accept being united with our declared enemies.

I'm not expecting an answer from you or any reader, just thinking out loud, but it seems important to bring such questions because a world peace is desirable&feasible, and despite all our flaws even capitalists are rational beings, there may be a way to concile everyone's interests and avoid what the future may hold for us, still not sure how but there's certainly ways.