This discussion is predicated on one basic assumption - that the propensity to strike a lure is genetically determined. That assumption is hardly a scientific fact.

Conversely, it could be that all salmon/steelhead have roughly the same genetic disposition towards lures but their reaction is caused primarily by environmental factors such as water temperature, physical condition of the fish, light levels, diurnal behavioral patterns, or, in the case of steelhead, nutritional deprivation (i.e, they're hungry).

Regardless of the reason, I wouldn't worry too much about breeding or, more likely, harvesting the aggressiveness out of the fish. They still have to eat, live, and grow in a very difficult environment (the ocean). To do this, they must have a considerable amount of aggression towards potential food items (shrimp, herring, smelt, etc). Otherwise, they won't be around long enough to return to spawn.