I personaly still think steel is superior to rugged long lasting firearms, or at least metal. Sure you can use plastics for most of the firearm and stick with steel for just the barrel, action etc..but that alone should tell you that only steel is strong enough to be safe and reliable under pressure, knocks, drops, and rugged treatment.
Personaly I know things made out of plastic that were strong and durable when new shatter to a light touch after years out in the sun. Plastic ages, metal if kept oiled ages very slow if at all, and even when it does it ages in layers while plastic's strength decreases throughout.
In short term use plastics work fine, but I sure would not be comfortable picking up a 50 year old plastic gun that went through a war and firing it next to my face. Even the military specifies designs utilizing more metal than civilian counterparts, take the Mossberg 590A1 vs the 590 (even though I think a steel Remington beats an aluminum Mossberg in durability.) It simply is a better long lasting strong durable material. Plastic on the other hand is cheap and easy to quickly mold and melt into shape, allowing it to offer cheaper production from cheaper material, and cheaper machinery required to cut and shape the material.
Because it is cheaper to use they will go looking for attributes to highlight, and there are some obvious ones. This does not mean is is superior or even ideal for guns IMHO. Yet because it is so much easier to make objects with you can get numerous custom or aftermarket parts in plastic as well. Cheap plastics allow anyone with the desire to implement thier design changes and make cheap molds to mass produce them.
As for Ruger, I agree his betrayal of American firearms owners is unforgiveable. Though I do understand why, he was trying to save his own neck and the right to design guns by deflecting the anti gun dems from banning guns, to pointing them at features.
Still you must admit Ruger firearms are tough and rugged, on par with well made soviet gear, and lacking in finess an precision just as soviet guns often are. A Ruger firearm will likely be around 100 years from now after firing tens of thousands of rounds, far longer than a Glock (unless rebuilt several times) or even thinner steel designed Smith & Wessons (comparing revolvers.) Ruger firearms are often built like a tank, lacking finess but lasting forever and taking whatever abuse is thrown at it. Of course if you don't want to support Ruger you could just buy a Russian firearm with the same qualities.