One might argue with equal justice that Isaiah 17 had been fulfilled in 636, when the Muslims conquered Damascus from the Byzantine emperor.
Or in 750, when the Abbasids reconquered it from the Rashids.
Or in 878 when the Sultan conquered it from the Abbasids.
I could go on, but the city has been sieged, conquered and reconquered a dozen times or more since the time of Isaiah.
I don't see how Sunnis seizing the city from the Alawites is any more of a fulfillment than these many previous incidents.
Plus.. the city being seized.. is a lot different than it being “in ruin”