The link below interested me as it's the other side of something I have read more about-- unconventional living arrangements. By unconventional, I don't mean sexually but just not the norm of male-female living together. It is discussing a changing view of family.
With older people this co-op living has been seen more and more as the economic conditions in the country become more difficult. Sometimes the people are living in quarters someone else created and charged a fee for the help provided. Sometimes a group gathers together finding they can live better together than alone.
But to see it be four men not yet 40 who have done it for eighteen years, where none of the four are couples, well that's a bit different.
The benefits are emotional and economic. Obviously they can live in better quarters by sharing them but there are emotional pluses. Wonder though what will happen if one falls in love and leaves home. Will they look for a fourth to fill out their budget needs?
It's not uncommon out where I live to see it be brothers or sisters who have just continued to live together. Or one child who stays with the parent both for economic reasons but also convenience and care. The reasons vary; but if it works, it's good and maybe more people need to consider optional living arrangements.