It seems like the balance of forces in Syria has hardly changed since the beginning of the civil war in 2011: apparently, neither the loyalists nor the rebel forces have the capability of overpowering one another.
Now, abandoning any kind of rhetoric, it is clear that, in terms of international security, a stuck conflict is far preferable rather than having one of the two parties victorious. Although it may appear to be an out-of-place statement, imagining the possible alternative scenario would be enough to see how truthful it is.