the socialism always goes for equalizing living conditions among different social groups of a society(for example - Sweden). Capitalism cares less about it(for example - USA)
But in general what matters most is economy, the better the economy the more people care about something beside food and shelter - Maslow pyramid is in action.
Could it be possible that USSR would have remained socialistic and have high life standards - yes, it would have(in some other time), Sweden is an example. Could have USSR be better economically if it would have been capitalistic, yes, it would have, the US is an example.
It's the matter of perspective.
I would say the more developed the country is(economically and culturally) - the more socialistic it would become. USSR was destined to fail because it was too young to be socialistic.
As for democracy - it does not exist, the same way as communism couldn't exist.