The disparate Syrian opposition that's been struggling since March 15, 2011, to topple his brutal regime was incoherent from the start, but has splintered, possibly fatally, with jihadist militants battling secular nationalists and even other Islamists.
Meanwhile, the United States and its Western allies, their eyes on an era-changing detente with Iran, Assad's key ally, now apparently are resigned to keeping him in power, even of a truncated state, rather than risk a rebel victory that could mean an Islamist regime in Damascus affiliated to al-Qaida.
Analysts say the Geneva II talks on Syria scheduled to convene Jan. 22 will reflect the new realities on the ground in Syria, with the moderate Western-backed opposition on the ropes and their arms supplies drastically reduced while al-Qaida makes big gains.
The war has stalemated. Neither side can score an outright victory. But the regime hasn't buckled and remains intact. The internal coup Western intelligence services had hoped for didn't happen. Assad's still the boss.
"There are increasing signs the United States and its partners are now willing to allow the regime, in some form, to maintain a role in Syria," Beirut analyst Lauren Williams observed.
Assad has long claimed those trying to topple him were "terrorists." And by accident or some Machiavellian intrigue, this is what's happened.
Some non-Islamist rebel officials even believe Assad has deliberately not engaged in large-scale operations against the jihadists, allowing them to flourish so they can divide his enemies.
Others talk darkly of a deal with the devil -- Assad actually coordinating with the jihadists to split the opposition.
"The notable absence of regime airstrikes in areas of northern Syria held by the Islamic State of Iraq and the Levant has led many to believe that the regime is intentionally enabling the group's growth to isolate the moderate opposition and validate Assad's horrific prophecy of Syria as an al-Qaida haven," said Daniel Nisman, Mideast regional intelligence manager at the Max Security Solutions consultancy.
On Jan. 1, the Syrian opposition's National Coalition declared it "believes that ISIL is closely linked to the terrorist regime and serves the interests of the clique of President Bashar Assad, directly or indirectly."
The coalition's accusation is understandable. ISIL and its allies are daily killing rebel rivals and, in coalition eyes, deliberately weakening a revolution that began with peaceful pro-democracy protests against Assad's minority Alawite regime, but was turned into a full-scale sectarian civil war by a brutal crackdown.
"For the Damascus dictatorship, it was an indispensable strategic goal to steer the uprising toward an armed conflict and ensure that it was as sectarian as possible, with the maximal amount of al-Qaida influence within the opposition," Lebanese analyst Hussein Ibish said.
Indeed, Assad has long had dealings with al-Qaida. During the Iraq War, he allowed jihadists to slip into Iraq through Syria to fight the Americans.
The Damascus regime has a history of harboring terrorist groups, mainly Palestinian radicals, throughout the 1970s and 1980s.
These were largely run by air force intelligence and carried out bombings and assassinations across the Middle East and Europe on behalf of Assad's perpetually plotting father, the late Hafez Assad.
"Theoretically, Assad and al-Qaida are the bitterest of sectarian and ideological enemies," Ibish noted. "But they have a well-established track record of knowing how to make each other useful, first in Iraq, and now again in Syria.
"It's impossible to know to what extent these organizations, their fighters, leaders and, most significantly, their regional backers intended to provide, or even understand, the invaluable boon they have been for Assad and his regime."
With the rebels fighting among themselves, and the jihadists emerging as the single most effective anti-Assad force, the West's confused, fumbling policies toward Syria and the refusal to provide the nationalists with heavy weapons has left Assad sitting pretty.
"Watching the muddle in northern Syria from his Damascus base, Assad is undoubtedly -- and unfortunately -- satisfied," veteran Mideast analyst Roula Khalaf said.
"Today he can claim more credibly that the unruly rebels fail to offer an alternative to his rule, no matter that it was his brutal killing methods that contributed to radicalizing and splintering the opposition."