Ideology is like McDonalds - fast food for thought. People choose not because of its taste but because of its easy availability and because of being inundated with it by authority figures (i.e. because of its low transaction cost and legitimacy, if you will). I am fairly sure that if for some strange reason the government in Washington adopted communism as its ideology, the majority of the American people would profess adherence to Communism, at least in public.
In essence, Communism in late 1940s had an appeal to young urban professionals and industrial workers in Eastern Europe because it gave them the power to climb in society (destruction of old institutional barriers to mobility, education, indiutrialization that created jobs) and provided a justification for that climbing (serving the progress). Sort of like the market ideology in 1990s. It then fell into disfavor when these upwardly mobile professionals hit a glass ceiling erected by the party apparatus, and the socialist economy slumped in early 1960s and did not churn up color tee-vees suburban homes in sufficient numbers. Sort of like post-Enron blues.
Being determines consciousness. Ideology is but an outgrowth of the material conditions of life and the occupational interests of the beholders.
wojtek