It is not about Julani being a failure or not. Tens of thousands of Sunnis died fighting in the SAA under Assad's command, these people have families, they have fathers, brothers, and so on. What happened in Syria was a civil war, if you expect one side to let go of its loss, you are daydreaming.
Last night, the streets of Tel Rifaat in Aleppo were filled with graffiti praising Assad and defying Jolani.
This settlement is Sunni. Jolani is such a failure that the people in the area now long for the days they once considered hell.