Without arguing with your thesis, the part about Havana is not true. Old Havana has been substantially restored to former glory, I believe that the UN or the EU paid for some of it.
The only good pics I have of Havana are near the Capitolio - just for the tourists it seems (the architecture is interesting, the old workmanship is outstanding, even for un-renovated structures - like the Roman Forum, they mark a time before La Revolucion when the city flourished).
I stayed just outside of Havana but travelled by bus and cab, so I saw a good cross-section of it.
Most of Havana appears decrepit, which is a shame.
Your statement may prove my point - no foreign or domestic investment, just foreign aid.
Communism is an analogistic idealogy/system, just like the 1950s cars that abound in Cuba.