First of all, let me clear up a few things regarding Marxism, and Communism.
1. There seems to be some confusion between 'Marxism' and Maoism. Fist of all, Marxism has not existed. Therefore, Marxism never exiled him from anything.
2. In discussing what 'Communism is' please understand that there are different types of communism the same as there are different types of religion. I'm not saying Communism is a religion, just stating the fact that there are, in fact, different types. In fact, there are different types of Marxism. It would be, actually, quite easy to apply some of these different methods (several of which are quite.... uhh.... secretariat and uh.... well... twisted) to just about anything. Also, I am not stating the the monk's are, I'm just trying to clear up a bit about communism/Marxism. It's far easier to divide 'communism' and 'Marxism' into tendencies.
Think of it like Catholic is the religion, the tendency would be 'Roman', 'Irish', 'Russian' ect. Related but very different in and of themselves.
3. The general Marxist view of what Communism is, is a 'stateless system'. Considering the state to be violence perpetuated from one (smaller) class to another (larger) class. Socialism is seen as the 'breakdown of the state as we know it'. In other words, a revolution in which the proletariat take control from the upper class bourgeoisie. The bourgeoisie being the %10 of the world that owns everything, and control just about everything. The 'revolution' is considered a multi-layered thing, with dialectical changes. capitalism -> socialism -> communism.
4. Marxism is mainly composed of three parts.
A. Dialectical materialism. - The idea that everything is ever evolving. 'change is always going to happen' sort of thing. You have a thesis, say a cup. The cup is the cup, A=A. Then there is the antithesis, not the cup. A (does not equal) b. However, there is also a evolutionary synthesis, The cup itself is always changing. The oils on your hand, natural breakdown, ect. So, we get that A (does not always equal) A from a given moment to the next. The thesis vs. antithesis to the synthesis, and a new thesis is formed. thesis -> antithesis -> synthesis = Thesis -> antithesis -> so on and so forth. Thus creating a constant state of change.
B. Historical Materialism. - The idea that dialectics, applied to history, actively shows a rate of change and evolution. Starting from the beginning, There was an anarchist/communist form of society in which life was composed of 'tribe' that took part in hunting and gathering. Food was little, so the 'tribe' worked together to gather enough food to sustain all the members. If there was not enough food to be found, the 'tribes' would often break down, or join with other tribes (according to needs) to make sure that everyone could survive. Eventually Animal husbandry, as well as horticulture were discovered. Because of this, 'tribes' no longer had to migrate. They could settle into an area (the early stages of land ownership) they also had something in which they had never had before- A (small) surplus of food. Everyone did not have to work all the time. From this, then, derived the first class system. Since not everyone had to work, people were able to learn from the things around them. To establish things like (in the far early day) cave paintings, they could study the stars, take greater care in finding out different uses for plants, ect. Thus you have the rise of the 'medicine man' and other religious leaders. This class system, at the time, was extremely progressive. However, in modern times, it clearly would not be. In the way of dialectics, (thesis) Hunters and gatherers-> (antithesis) Starve -> (synthesis) Find a better way = settle and grow crops and raise animals. An evolutionary change.
Thus, he doesn't have thousands of years to overthrow, in fact, he only has a hundred or so in which most of the world was in the vein of capitalism. The caste systems before have already been overthrown by the system that followed them.
It happens in almost every system we have had. The Thesis, turns around and makes for it's own destruction via a progressive step. Early anarchism/communism hunter gatherers -> the progressive step was different forms of 'slave societies' which lead to the creation of writing, language, medicine, ect. -> the progressive step was to change to feudalism, which allowed for more prominent cities to develop, start the building of factories, a more heavy monetary exchange, ect. -> the next progressive step was Capitalism, which built even more factories, created the working class, even more technological advances, ect. - the next progressive step (in the Marxist train) is socialism, more economical equality, health care for all, a better standard of living, higher quality of life, ruled by the majority, ect. -> the next step would be communism, and so on and so forth.
c. Marxism economics. - This is kinnda hard to explain in my own words. So I am going to link and quote to make sure this is explained a bit more clearly. http://www.marxist.com/what-is-marxism-economics-materialism.htm#economics
To begin with, all the capitalist firms produce goods or services, or more correctly they produce commodities. That is a good or service produced for sale only. Of course, someone may make something for his or her own personal use. Before capitalism existed, many people had to. But this is not a commodity. Capitalist production is above all the creation and "immense accumulation of commodities". That is why Marx himself started his investigation of capitalism with an analysis of the character of the commodity itself.
The law of value governs the price of goods. As explained earlier, the value of commodities is equal to the amount of labour contained in it. In theory, the value is equal to its price. Yet, in reality, the price of a commodity tends to be either above or below its real value. This fluctuation is caused by different influences on market price, such as the growth of monopoly. The differences of supply and demand also have a great effect. For instance, there may be a surplus of a commodity in the market, and the price that day may be far below the real value, or if there was a shortage, the price would rise above it. The effects of supply and demand have led bourgeois economists to believe that this law is the sole factor in determining price. What they were unable to explain was that prices always fluctuate around a definite level. What that level is, is not determined by supply and demand, but by the labor time spent in the articles' production. A lorry will always be more expensive than a plastic bucket.
You should read the whole article.
I'll leave it at that for now.