It's GREAT when it WORKS. And it DID - for my paternal grandparents, who had a rich and warm family household. My in-laws, on the other hand, ended up living in little in-communicative islands (rooms) with the minimum of open, comfortable interaction. Not any scene I would want to live in.
The article identified some key points - it's very much about The Money (shares expenses), there WILL be a "power structure" (someone owns, someone else is/are the folks moving in to share it, and some pay more than others), and it (may) promotes an "older way of (more) communal life". All Good Points.
It left out almost entirely the key deal-makers and breakers involved with sharing a household: 1) ALL must get some benefit - and RECOGNIZE that they are getting a real benefit - from an arrangement to be happy and cooperate within it. Folks are NOT happy just "sharing their space" or maybe "sharing the bills" - try the "room-mate scene and look at why that so often fails. I am not happy with telling YOU to clean up your mess. 2) ALL the players must have real RESPECT for all others - including recognition of "position" and its perspective. You MUST accept that others have rights and perogatives - from the git-go. Or be certain of a fight.
I have no desire to share my house with my almost-adult children. It's no judgement on their worth - just recognition that we want different things. Maybe after they have experienced and learned to step into and be comfy with personal and shared responsibility, but only after that is well-demonstrated. They received basic living-skills training - now they have to practice and polish them up to become full-participants in a household of even near-equals (but we will NEVER be equals - households are neither communes nor free democracies). I want to regain MY perspective on MY life. Their lives need to be under their control and become their responsibility. I do NOT want to be their go-fer, janitor, bill-payor, provider, etc. (And yes, I suspect that they don't wish to become my keeper and care-giver when I'm older... but that's almost a different subject!) Your minor children are not your equals, and should not be considered or held to be. When they become adults, they, like you, will have to still work on and polish their skills and develop their perspectives and attitudes towards others.
So - children, parents, the elderly.... different perspectives and roles. The parents paid for and raised their kids and prepped them for presumably successful lives. The kids will eventually inherit the parent's estate. So, it seems a not un-fair expectation that they should come to help and maybe care for the aging parents. But all this is expectation and trust about once (but no longer) fully-accepted roles within extended families. IF you have not established those roles and understanding BEFORE THE FACT, and cannot comfortably talk about them now, your multi-generational household will fail.
We are not, as a society, actually fostering any "family-first" vision in anyone - witness the growing generation-war over Social Security, taxation, etc. IF the ME attitude, as revealed in that difficult and acrymonious discussion, occurs within a family house-hold.... no way! For the family to work, EVERYBODY has to recognize that being there is BETTER than being somewhere else. We are now encouraging an "us vrs them" struggle for power and control. There is simply no room under one roof for this. Someone will have to make the decisions and be in charge and be responsible, and others will have to accept and BE HAPPY with their roles.
Consider that over 50% of marriages end in divorce. And anyone think that the attitudes and approaches and respect and negotiation skill and willingness to cooperate which is apparently so lacking there will be magically available to support being "married" within a multi-generational household? Tooth fairies!