How has the government in 1984 alienated not only Winston, but the population in general? What basic elements are being denied to these people that have led them to their present situation? Could this happen now?

Those are loaded questions but I'll try my best. The outer party is beyond alienated. At least Winston still feels something. Most other people in the outer party are so conditioned to eradicate feeling that they simply go about their day like brainwashed lemmings. The Party uses fear and paranoia to reshape human behaviour and even thought process. Really any sense of individuality and personal happiness is being denied members. In a broader more benign sense most everything in 1984 happens today to an extent. We are conditioned to accept the status-quo for fear of looking or being "different".