It depends how you measure wealth. If the whole world was shared by the whole human race, everyone would have the whole world as a playground. As it is you can barely take a step off the road without infringing someone's 'property rights'
With due respect, I think you're impression of what the world was like before modern conveniences is grossly misguided. You call the world a "playground"?
You realize that you're still perfectly able to return to that state of living. Give away all your "useless material possessions" and go live in a national park or up in the vast open territory in Canada. You can live just like they did thousands of years ago. There's absolutely nothing stopping you from doing this.
The "playground" you speak of was anything but. Nine out of ten of us chatting about this would already be dead, and the other would be perpetually hungry and terrified of the impending winter.
There is a reason men have labored continuously over thousands of years to escape this "playground." Yet, you complain because the idea that some people own property bothers you? You'd rather just have everyone destitute, afraid, and starving... so long as everyone was equal in this misery?