The chief reasons are artificially low pricing (it's almost free, so people have no incentive to conserve power, and the utilities are starved of funds for maintenance) and poor administration (this has been a long time coming -- brown outs and black outs have been endemic for some time).
They are simply running the country into the ground thru mismanagement and negligence.
The option to let things happen (by removing regulation / price-controls, etc), or for scrapping and starting fresh appear to never be on the table in any meaningful respect.
It's like they try to run the country on ideals alone and that ideals will carry the day.
We're not a basket case economy in any stretch of the imagination. Compare and contrast.
That's all it is, tbh, without resorting to hyperbole. This happens even in capitalist economies -- companies have little incentive for maintenance at the best of times.
IMHO, when 40% of energy for the whole country is provided by one single plant (regardless of plant type), things will go wrong at some point. To overcome a situation like that you need money and vision to build a redundant system. Clearly the Venezuelan government lacked them.
Have you actually looked at the maintenance budget of US utility companies?
At least it states the reason why in the first paragraph: hydro-generation is at risk because of a prolonged drought.