Well I agree with you on some points. I think that the radicals on both wings of the political spectrum have a lot in common with each other. The fact is that Anarchism is the point in the political spectrum where Marxism and Libertarianism collide.
Anarchism rejects the power of the state or the importance of the state, similar to Libertarianism while it also rejects the idea of private property like Marxism.
However I don’t think you can compare either one of the above ideologies with capitalism simply because capitalism isn’t really a political ideology.
I believe capitalism is just a natural system of the free market or perhaps simply the market. I’d compare capitalism with a river.
Marxism wishes to completely dam the river and build canals around and secure the banks against any kind of flooding. Now Libertarianism believes that the river is somehow a sentient being and that building dams will lessons the rivers flow up to the point where there is a heavy downpour and the dams break.
In the Libertarian case the river floods the banks every rainy season destroying property and lives while in the Marxist example the pressure builds up and the constraints of the river make it break through the dam thus also destroying property and ruining lives.
I believe both of the named ideologies are extremes and the true way is the middle path.
Ironically both ideologies want the best for the people and both want freedom. The difference is that Marxist want freedom from the yoke of factory owners, landlords, landed gentry, magnates and generally the privileged class while the libertarians want freedom from the government, bureaucracy, regulations and generally any institution of the state.
As I said before I’m for a middle way. I don’t believe in complete deregulation nor in complete regulation of the economy. The river should be able to roam free in places but be dammed in some spots as well.