In 1984 by George Orwell, why does the Party own everything?

In 1984, the Party claims it owns everything in Oceania for the "good of the majority" (Part Three, Chapter Three). In reality, the truth about the Party's ownership is far more sinister: the Party owns and controls everything, from housing to razors, to keep the people of Oceania in a state of dependence. This view is supported by O'Brien who, in Part Three, Chapter Three, reveals the reason why:

Obedience is not enough. Unless he is suffering, how can you be sure that he is obeying your will and not his own? 

In other words, by controlling everything in Oceania, the Party guarantees the public will stay loyal. They will do this because they need the resources the Party owns and controls in order to live.

Moreover, as we see from the above quote, the Party deliberately keeps living standards low and certain items in short supply. Again, this guarantees that people will stay loyal because they are suffering and people who suffer are far less likely to rise up and overthrow the Party, provided they are unaware the Party is the cause of their suffering. Instead, the people are forced to rely on the Party to help them, thereby reinforcing their state of dependence.