I will surmise that spending money freely (on expenditures such as dining out) was probably rare for those who either lived through the great depression a.k.a dirty '30s (few in numbers these days) - probbly such as your parents - or their children and perhaps even grandchildren. The event made a very profound and lasting impression, instilling a great sense of thrift for a couple of generations. The great recession some 80 years later brought some of that back which resulted in some restaurant bankruptcies. Perhaps good times and easy credit (through credit cards, the use of which was still a bit of a rarity in the early '70s?) precipitated the right environment for a new slew of restaurants to cater to the mass market, much as cruises used to be exclusive.