Not so much the west in general, Southern Europe do nice things with veg. Cant speak for other countries, but in the UK it seems to have been a combination of

Not so much the west in general, Southern Europe do nice things with veg. Cant speak for other countries, but in the UK it seems to have been a combination of servants getting too expensive for middle class families, so House wives, who didn't previously need to cook, now suddenly having to learn (A special mention goes out to Mrs Beeton for teaching people to overcook things), and rationing and general shortages during the world wars.