Hmmm... I agree in part, but I'd like to do some knitpicking.
I think some social groups will succeed more than others regardless of economic structures... And I'm okay with that, so long as the relationship between people isn't exploitative.
As it stands, it is extremely exploitative, and I'm sickened by the wasted potential. If we can at least ensure that people get healthcare, a place they own, a share of natural resources, clean water and nutritious food, then things will level out a bit.
Combined with major adjustments to the function of government, we'd be on a solid track. Governments need to be making investments into sovereign wealth funds. They need to put into place technological solutions to the voting problem. They need to make major changes in food policy and urban planning. And we need to put way more money into productive scientific endeavors, such as funding for clean energy (lets make plasma happen), space exploration, robotics, and global internet connectivity.
At that point, I'd say we'd be ready to go full post-capitalist. But it's not within reach yet. I think your expectations are maybe a bit too high.