Topend, the theory goes that the root end of the blade is stalled because of the high AoA caused by the low speed of the inboard section and the high RoD.
The tip and outboard section is in its own recirculating vortex and not producing any useful lift.
This leaves the bit in the middle of the blade (a ring if you will, hence the name) which suffers unpredictable airflow due to the wandering of the tip vortex and the root stalled area.
The airflow coming at the disc from underneath is therefore somewhat erratic and causes random pitch, roll and yaw making control of the helicopter much more difficult.
This is one reason why some people say enter auto to escape VRS but you need a lot of height to do it.
Forward cyclic, if held long enough, should fly you out but , as TC has said, you really don't have much control at all.
The answer is to avoid the entry conditions and know how to recognise and recover from the incipient stage.
I think modern helicopters with higher hinge offsets and therefore more control power are probably easier to recover in - having said that they also have higher disc loadings and therfore need a higher RoD to get into VRS in the first place.