Observers suggested the powers that be in Havana may actually be angling for more time as they struggle to build a consensus over the path ahead.
The vote comes as Cuba's thaw with the United States under President Barack Obama has turned frosty under the Trump administration, and as its own hard-liners question just how fast the island nation should embrace reform. Meanwhile, one of its closest allies — Venezuela — is mired in a deep economic crisis, unable to provide Cuba with as much cheap crude as it used to under an energy-for-doctors deal struck in 2000.
"They're very nervous about this transition," said Michael Shifter, president of the Inter-American Dialogue, a Washington-based think tank. "It's going to go forward, but the Trump administration has thrown a wrench into their thinking, and they want to make sure things are going to go according to plan."
Obama's historic visit to Cuba in 2016 — the first by a sitting U.S. president since 1928 — promised a new dawn in long-problematic U.S.-Cuba relations. But the prospects for change have darkened.
This year, U.S. officials said that at least 24 American staff members and spouses attached to its embassy in Havana were the victims of a mysterious attack that left at least some with brain trauma, affecting vision, balance and memory. Cuba has strongly denied any wrongdoing and protested the October expulsion of 15 of its diplomats from its new embassy in Washington.
President Trump also has curbed the less-restrictive rules on Americans traveling to Cuba enacted under Obama.
The Cubans, meanwhile, have sent conflicting signals.
Hard-liners have been pushing back against an accelerated economic opening. In August, Cuba at least temporarily suspended new business licenses, including for bed-and-breakfasts and restaurants. In October, however, the nation's Foreign Ministry appeared to offer an olive branch to Cubans who fled the country in the 1950s during the Cuban revolution, introducing rules that make it easier for them to visit.
"There is a clear battle between those who want to speed up and those who want to slow down economic reform," said Geoff Thale, a Cuba expert at the Washington Office on Latin America, a think tank.
It remained unclear whether Thursday's move signaled an attempt, preferred by some on the island, to keep Castro as leader for even longer.
The man currently tapped for the job of leading a post-Castro era is First Vice President Miguel Diaz-Canel. The 57-year-old was born after the revolution, and his ascension would signify a new generation of leadership.
Some have suggested he could be more of a moderate, though there is evidence to the contrary. A leaked video of Diaz-Canel in a private meeting with Communist Party members showed him threatening to block a website — OnCuba, which he accused of being "very aggressive against the revolution" — and accusing European diplomats of subversive activities in Havana.