During the Cold War, the US and USSR meddled and most places where they meddled, the people there weren't the better for it.
We were not the same during Cold War. Socialism had large popular support everywhere except the Western World.
USSR was usually invited, whereas you were trying to stop it by any (mostly illegal and criminal) means necessary
In the end, Socialist System proved to be inefficient and lost economically.
China may prove that this loss may have been accidental.
If socialism was so popular why hasn't it survived?
The Russia/China flavor of "socialism" has always been about putting a strongman in control. Never about the people.
There are two orthogonal axes here.
Socialism/Capitalism and Totalitarianism/Democracy
None of the four extremes make for a pleasant life for everyone; Maximising how pleasant things are, and for how large a fraction of society, requires a balance on both axes.
And each activity in society requires a different balance. Food production and distribution doesn't have the same optimum balance as transport infrastructure, for example; Neither has the same balance as defence; healthcare; law and order; etc.; etc.
The OECD nations have in common a similar set of balances; And are differentiated by both their choice of those balances, and the hypothetical optima given the cultural expectations of their people.
Basically, nice places to live have governments that tend to try to move things towards their nation's optima, and to resist moving them away from those optima; And one of the most important ways that governments can achieve this is decentralisation of power - having a lot of people with varied agendas making decisions is usually a good thing; Putting one person, or a group of people with a shared agenda, in a position to make decisions (while disempowering anyone else) is generally a bad thing.
Of course, there are some circumstances where a quick decision is more valuable than an optimal one; Such cases require a President, Pope, Prime Minister, First Secretary, or other dictator who can just make decisions. But crucially, such crises are more common in dictatorships, where decisions are inevitably suboptimal.
And Presidents, Popes, PMs and First Secretaries tend to want to accumulate as much power to themselves as possible - they are self selected for that desire for power - so to break away from (or avoid collapse into) dictatorship requires strong separation of powers, and a longstanding commitment from at least one powerful branch of government to the maintaining of that separation - a task which itself requires the power to impose that commitment on any wannabe dictator (and all holders of executive power tend to be wannabe dictators).
Russia (in its tsarist past, socialist recent past, or feudalist/neo-tsarist present), has never had a tradition of widely distributed power.
People are frequently derisive of consensus driven "government by committee", and its central shortcoming - difficulty in making timely decisions - is well known. But in a reasonably pleasant society, most decisions that cannot garner consensus support are decisions that shouldn't be made. Change is necessary, but if only a tiny group (or a single dictator) sees a specific change as desirable, it's probably harmful.
A government that struggles to get anything done is a good thing. Certainly, such governments rarely decide to invade their neighbours.