Assad was only able to take back Syria with air support from Russia, ground support from Hezbollah and re-enforcement by Iran and other Iranian aligned groups in Syria.
Russia is busy and drained of resources because of its misadventure in Ukraine, Hezbollah is reeling from it's shocking loss to Israel while Israel has been targeting Hezbollah and anything vaguely tainted by Iran in Syria for years now. Iran itself is being very careful with that it's doing after losing so much of the long-term strategic positioning it invested in.
All of that, that was what was holding back opposition. SAA couldn't have done it in the first place without that support and that support later became security while SAA had other things to do. When it was weakened, the opportunity began to exist.
My personal opinion is that it's been a while since that security actually existed and due to all of the above mentioned problems, it's been a bluff for longer than it has seemed. When the Aleppo lines collapsed, HTS figured this out and acted swiftly to take advantage of that fact. SDF and the southern front joined in when they say they were having so much success.
Taleb should know better, or not be commenting. It makes it sound like a conspiracy theory or something.