How and why is the inner party social group represented in a particular way in 1984?

We are given
only a few glimpses of the lives of inner party members. However, those glimpses show us that
this small group of party members live lives of luxury that are completely different from those
of outer party members or proles.

manages to find access to inner party
resources. For example, she brings real coffee to the room above Mr. Charrington's shop. This
coffee is quite different from the foul imitation "Victory" coffee outer party members
drink:

"Its coffee," he [] murmured, "real
coffee."

"Its Inner Party coffee. Theres a whole kilo here,"
she said.

"How did you manage to get hold of all these
things?"

"Its all Inner Party stuff. Theres nothing those swine
dont have, nothing. But of course waiters and servants and people pinch
things..."

Not only does Julia procure the coffee,
she notes that "there's nothing" the inner party "swine" don't have. She
mentions, too, people (waiters and servants) completely absent from the lives of people like
Winston and his peers.

Julia and Winston also get a brief view of inner party
life when they visitshortly before they are arrested. As they step inside his apartment, Winston
notes the dark blue carpet which looks like velvet and thinks:

The wholeof the huge block of flats, the richness and spaciousness of everything, the
unfamiliar smells of good food and good tobacco, the silent and incredibly rapid lifts sliding
up and down, the white-jacketed servants

The walls of
O'Brien's flat are creamy white and spotlessly clean. All Winston has ever seen are grimy walls.
Both he and Julia are completely surprised that O'Brien can turn off his telescreen, something
forbidden to them. Moreover, O'Brien has his servant serve them wine, a drink they have never
had and which Winston comically gulps down instead of sipping it as he should.

The gap between inner and outer party members is huge, a chasm. This is done on
purpose, as explained in Goldstein's book, The Theory and Practice of Oligarchic
Collectivism:

if leisure and security were
enjoyed by all alike, the great mass of human beings who are normally stupefied by poverty would
become literate and would learn to think for themselves; and when once they had done this, they
would sooner or later realize that the privileged minority had no function, and they would sweep
it away. In the long run, a hierarchical society was only possible on a basis of poverty and
ignorance.

The inner party is the tiny elite that runs
the society. Although enough resources exist for everyone to live comfortably, the elite fears
this because they are afraid that if the common people had the time and energy to think, they
would throw the elites out of power. The inner party is fixated on holding onto power above all
else. Therefore, they waste society's resourceswhich could be used to raise the standard of
living to a decent level for everyoneon unnecessary wars so that they can keep their grip on
power.

Also, as O'Brien will later tell Winston, the only way you can be sure
you have power (at least in his opinion) is if the people below you are suffering. Therefore the
inner party keeps the standard of living between them and the outer party members as far apart
as possible.