Your chances in a small storm cycle soft slab are decent as long as there is no terrain trap and you don't get slammed into a tree or pulled off a cliff (which is fairly common since cliff bands increase the likelihood of release). That being said we just had two people die this weekend in Teton County due to soft slab failure at only 8 inches. Both were killed by trauma from collision and not burial (SIP).
If you manage to propagate a deep layer hard slab then you might as well kiss your ass goodbye. Where as a soft slab will often release at the first point of contact, a hard slab is more likely to trigger once your well exposed on the layer. An ABS pack might help keep you on top, but just the forces of the snow in a large slide potentially could kill you.
Sooo... when you say the proper equipment gives you a "pretty good chance of survival" that's assuming you don't die before before the snow comes to a stop. If you do, and your now frozen 3 meters down in snow as hard as concrete, hopefully your partners are competent enough to find and dig you out in 10-15 minutes.
My point being that faith in equipment is faith misplaced. Strong terrain evaluation, local snowpack knowledge, and proper decision making, is more likely to save your ass by keeping you out of the slide in the first place.
Another worthy resource:
