"The main role of the CIA, from the time it first intervened in 2012, was to block the anti-Assad opposition forces from acquiring the arms necessary to bring down the regime. The most the CIA was prepared to allow was for the opposition to put sufficient military pressure on Assad to force the regime to accept a negotiated settlement.
"The rationale for the arms program was, from early on, muddled. It wasn’t supposed to make rebels win outright. ... instead, the U.S. government tried to use a remotely managed proxy war to force an extremely delicate, negotiated political resolution."
So much for your fantasies about "regime change".
After Daesh took Mosul in 2014 even that limited support was increasingly withdrawn, as the US tried to push the opposition into abandoning the struggle against Assad and taking up a fight against Daesh instead. The Southern Front of the FSA has been completely demobilised since the beginning of 2016 because the CIA withdrew all support from FSA groups that continued to fight Assad.
I've read that Turkey and Qatar had already proposed to step in and support the Southern Front. If that's the case, Trump's cancellation of the CIA programme could be a good thing. The opposition would be able to resume the struggle against Assad, without being pissed around by the US as they have been for the last five years."