I haven't checked it but some культуролог once told me that during Stalin's time дачи were distributed among the political elites and intelligentsia (so it was kind of a 'status symbol', of course it was not a place to grow staples there). Only later дачи are becoming as we know them now. As far as I remember there is something like дачный посёлок писателей in Большое Переделкино near Moscow (so these are this kind of дача).