Probably right.
They ask for Zelensky’s removal. That’s an item that likely can’t happen until they continue their advance further.
Their other demands are what they are, but it is the Zelensky removal demand that won’t happen. Zelensky won’t resign, regardless of military situation. Vance has this right.
Unless we make Z an offer he can’t refuse.
Basically demanding that Ukraine disarm without any security arrangements isn’t going to fly either. Another name for that is unconditional surrender. Russia could waltz in later with no opposition.