High oil prices allowed Chavez to get away with subsidizing the price of staple goods. But without some outside money source, you have to run a socialist economy by rationing. Where there is rationing, you have to make black markets illegal. But the only way the system can efficiently allocate goods is through a price signal, which black markets provide.
So, for the system to exist, black markets must operate. In order to operate, black marketeers have to pay off government officials. People who want to buy goods have to pay off government officials. Increasing amounts of brute force are required to keep everyone in line.
We’ve seen one socialist government after another collapse into dire tyranny throughout the 20th century. That people still support socialism in the 21st century shows remarkable resistance to the lessons of history.