Well, when your really think about it, there's a lot of SKS in all of these firearms... so they are in fact improved versions of the SKS, which itself was inspired by previous rifles like the Kar 43. Each of these rifles evolved from something that preceded it.
I often wondered which rifle I'd prefer as a camp/bush or wildlife defense gun if AKs were legal in our dumbass Liberal utopia, as they should be... and my vote would still go to the SKS. It's cheap, tough as nails, works every time and it has a low profile integral mag that doesn't get in the way. With our retarded 5 round limit, a detachable 5/30 round mag has no practical purpose anyway for utilitarian reasons and would only be a hindrance to carry around.
The SKS is king of affordable/durable semi-autos and does what it was designed for extremely well. In fact, a better design could not exist to fill that specific niche. There are few SA firearms out there on which you can trust your life no matter the conditions (desert, jungle, rain, mud, freezing cold); the SKS is one of those rare firearms. Whoever laughs at these iconic rifles is an idiot with insufficient mechanical and historical knowledge, not to mention range time.