The (well deserved and smart) attacks by the USA and Israel in Syria will give the new terrorist regime a reason to keep the Russians in place.
This will be good as the Russians will serve as a counterbalance to Turkey and the more extreme Islamic influences.
Your comment pretty much indicates that you don’t understand where Russia and Iran were in this war. They won’t stay because the people that won, were bombing and killing the Russians two days ago. There isn’t much of a chance that they are allowed to stay.