That's not a black and white question. Possibly yes, it depends entirely on how and why the motherboard failed. For example if you have a cheap power supply which let a surge through it could fry everything connected to the power supply. If you blow a capacitor or your mobo or the VRM fails, the motherboard would fail but everything connected to it would likely be fine. There are countless different ways a mobo and surrounding components could fail, some may result in other components dying as well, some may not.