The Libyan insurgency probably continues on for a while and Qaddafi and the rebels trade control of the coastal highway back and forth, and eventually, the Rebels gain enough momentum to repeat what they did, albeit perhaps 9-12 months later than OTL.
It is a such a lazy trope that exists that assumes that the Libyan Civil War was only won by western intervention and tsk-tsking about blowback, etc. Western self criticism is one of the most blatant forms of ethnocentrism that exists these days, but thats a topic for another day.
In reality, during first Civil War, the Rebels had recieved quite a lot of defections before the first bit of NATO assistance, and massively grew in volunteer support. Qaddafi's support was limited mostly to the Tripoli area and a few loyalist pockets, with some tribes that were on his side because rival tribes joined the rebels. The Libyan Air Force was the big reason why his counterattack initially picked up steam, but they were almost completely out of fuel by mid March. In fact, while NATO would have annihilated the Libyan Air Force in air to air combat, they were mostly grounded because of fuel issues by the time of the intervention.
That is not to say that they wouldn't have gotten creative, as Assad has, with his use of helicopters for rudimentary carpet bombing and terror bombing. But the big aerial assaults that went with Qaddafi's March 6th counterattack were not going to have continued without a major fuel resupply. Perhaps Russia or someone else would have supplied it, I don't know.
In terms of Libyan population polling support for the NATO intervention, the results are shockingly pro-bombing, with over 75-85% support for the action as polled in 2012. Considering that it amounted to foreign air forces dropping bombs on Libyans, that indicates that support for Qaddafi was probably even more paper thin on the ground than previously thought.
The idea that Qaddafi was well positioned to put a decisive end to the rebellion in mid March 2011, or that he commanded broad or even a plurality of support, is incorrect. The one bit of success he had, some brief victories on the Brega road to Benghazi, were not decisive enough to make a taking of Benghazi likely. It is true that the destruction of most of Qaddafi's infrastructure of defense was destroyed as Benghazi was attacked, and that some armored vehicles were taken out by French intervention, but the attack was ultimately beaten off by rebels on the ground. And even if Benghazi was taken, there is no reason to think that a counterattack wouldn't have taken it back, or that other fronts wouldn't have turned out the way they did (like in the West, or the other areas of the coastal highway).
The one area where Western intervention was decisive was in making the Rebel's path into Tripoli and Sirte easier than it would have been otherwise by taking out hard targets. But that merely sped up what was inevitable.