In 1984, what realization does Winston make regarding the proles?

In chapter seven of Book One, Winston writes in his journal, "If there is hope . . . it lies in the proles" (Orwell, 89). Winston Smith realizes that the proles make up the vast majority of society and account for 85% of the population. He mentions that if the proles ever became conscious of their own strength, they would simply rise up and easily defeat the Party like a horse shaking off flies. Unlike the callous, frightened Party members, who are aware of the Party's strength and oppressive tactics, the proles have relatively free lives and are almost forgotten by the Party. The proles also possess a vague sense a love, family, and loyalty to each other, which is demonstrated when Winston witnesses a prole woman cover her child's eyes during a graphic scene at the movies. However, the proles are too ignorant to understand their oppressed status or recognize their own strength. The Party views them as mere animals and understands that they are completely ignorant citizens, who are only concerned about consuming and satisfying their primitive desires without posing a real threat to authority. Despite their ignorance, Winston believes in their strength and innate sense of humanity, which is why he writes that hope lies in the proles.

In the first line of Part One, Chapter Seven, Winston has an important realization about the Proles:

'If there is hope,' wrote Winston, "it lies in the proles."

In other words, Winston is saying that if the Party is ever to be destroyed, then the Proles are the people who can do it. This occurs to him because the Proles constitute 85% of the population of Oceania. Therefore, they represent an overwhelming majority.
The problem, however, is that the Proles lack any desire to change things. Although they are segregated in separate districts from Party members, they are left to live their lives however they choose. They are not subject to Party rules and regulations. They can marry who they want, drink and gamble, and do not live in the shadow of the telescreen. In essence, they have no reason to rise up against the Party. 
The Proles are the only people who can change the social order, but, as of yet, they have no desire to make these changes.