Re: Scarcity of resource
You totally can have 75% of the populace being poor. History shows us that's the norm - the golden age of the middle class in the late 19th-20th centuries is an outlier - and make no mistake, if the invisible hand is allowed to govern everything in its own way, we'll be back there in no time.
The question is whether that's what we want. Because we have the tools, now - democracy, economic models, government infrastructure (or "bureaucracy", as Tim would probably call it) - to do things differently.
If we want to.