I haven't lived it as per se but people seem to romanticise multi-generation living as being some sort of utopia and the answer to everything. I work in adult social work and have come across a few situations like this, usually people from different cultures and they've all been without exception ended up an utter shit show. Scenarios such as toddlers and adults with advanced dementia living under the same roof with no care packages in place because it's the expectation that family will look after the elderly. Except its never the whole family, it's usually one poor woman or two, completely and utter burnt out and on the verge of a nervous breakdown.
And a lot of people seem to romanticise as well, the 40s and 50s where people had big families and all lived close together. All my grandparents came from large families of over 10 children and they all lived in very small flats with outdoor toilets. And when all the children grew up and had their own families, there was no grandparent help as the great grandparents had so many children they couldn't possibly dedicate time to them all to help out and siblings were so busy with their own families they had little time to help others out.
My mums own mum worked in an early morning cleaning job while her children slept in bed at home alone which would obviously never happen now. My other grandmother did night shifts as a nurse. While both grandparents were then at home during the day, their main job was housework and cooking without all the modern appliances we had now. Kids would be turfed out onto the street to play.
I feel even though I work full time now my son gets more 1:1 time with me than my parents did with their parents too. My parents say the same even though they hold absolutely no resentment and very much loved their own parents, just a different time!