Oil output peaked the few years prior to Chavez taking over and then began a persistent decline. Oil exports boomed from 1987 to 2000, going from 1.5m to 3m barrels per day. Under Chavez that collapsed by nearly 50%. Maduro of course has just continued the trend line.
"Days after the [Maduro] recall movement was cancelled, 1.2 million Venezuelans protested throughout the country against the move"
https://en.wikipedia.org/wiki/2017_Venezuelan_protests
"Huge marches as Venezuela marks 50 days of protest"
https://www.aljazeera.com/news/2017/05/venezuelan-opposition...
June 2017 "Beginning on April 1, anti-government demonstrators have staged daily protests across Venezuela that continue to devolve into violent clashes with riot police, leaving thousands arrested, hundreds injured, and 66 dead."
https://www.theatlantic.com/photo/2017/06/months-of-anti-gov...
The centralized economy enabled Maduro's government to co-opt food distribution and election security apparatuses to make the protests fruitless. TL; DR An organized dictator can survive economic collapse longer than one might expect.
"Voters who used their Fatherland Cards were given food at a quarter of the polling stations surveyed in December by Torino. At some other sites, voters were instead told where they could pick up the food.
After voting, Katerina Noriega, a street vendor in Santa Rita, was directed by Socialist activists to a warehouse to receive a couple of pounds of rice and beans, worth about 10 days of work.
'They bought our votes,” said Ms. Noriega, who acknowledged supporting the government candidate to get the free food. “I did it because of our difficult situation.'
...
The so-called Fatherland Card, using technology from Chinese telecom giant ZTE Corp., allows the government to keep track of who has voted. That permits officials to put pressure on food recipients if they are reluctant to cast a ballot, according to election experts, government critics and ruling party activists.
By law, the vote is supposed to be secret. But at voting centers in the capital, Caracas, and the westernmost state of Zulia during the December municipal elections, it was easy to see how the ruling party worked the levers of government to ensure that likely supporters made it to the polls. In a giant red tent, Socialist activists scanned voters’ Fatherland Cards. Using a computerized database, they could determine who hasn’t voted and what benefits those people receive. Government supporters called “patrollers” were then dispatched on motorbikes to the homes of food recipients to remind them of the benefits and convince them to turn out, according to a local ruling-party official."
https://www.wsj.com/articles/venezuelas-maduro-clinging-to-p...
The average Venezuelan reported losing 24 pounds [1] of body weight just in 2017 from lack of food. The system won't survive much longer. They're at a stage of collapse where cannibalism will probably start to show up. People are flooding to Colombia and Brazil. The army will very likely remove him sooner rather than later. There's no cult loyalty system built up around Maduro as with someone like Kim Jong-Un for example.
[1] https://www.reuters.com/article/us-venezuela-food/venezuelan...
A dictator can stay pretty long with enough force.