If, within a few minutes you aren't able to revive the fish to the point where it remains upright, and tries to swim off, the chances of survival are probably pretty slim. However nothing is absolute, and steelhead in general are pretty tough fish. Also you would probably have to fight the fish for a very long time to tire them to the point of exhaustion. IMHO, as long as the fish isn't hooked deep in the throat, or gills, and you fight them agressively with the proper tackle, don't drag them out of the water, remove the hook and release them carefully, their chances of survival are pretty darn good.