Yes, it absolutely does.
In terms of breakdowns my assessment is that they have shown pretty good capability in repairing their vehicles. They don't necessarily lose vehicles due to an inability to maintain them. But, yes, they're vulnerable in this regard.
I would provide a caveat, though, a bit of caution. If they can't fight like a conventional military anymore, they might revert to fighting like an insurgent force. They were actually very successful in Anbar province in late 2014 in an offensive led by Omar al-Shishani, who's a Chechen field commander, who basically, in rampaging through Anbar, captured the city of Hit during that advance. They fought very much like an insurgent force, going in and capturing territory; that is, they had light forces and good speed of movement. They didn't have these big columns, the kind of things that ISIS in many places is characterized by. If they resort to insurgency warfare, that does create its own sets of vulnerability, but the bottom line is it makes it more difficult for them to maintain their territorial holdings.