There is the idea that, although a family with an only child or only son and only daughter might find there are issues with "lonely only" cravings for siblings, keeping the family circle "mean and lean" may be better for CLARITY in the life path and in fact be the better way.
I do not know about better...but it is different in some ways. Though loneliness happens, it happens anyway, and I have learned like living alone: at least, as I do a great day and "workarounds" on the challenging ones, my moments do not cause issues for others. I never suffer the feeling that I am preventing anyone from pursuing their goals and needs. I am lucky in enjoying a fine home and family love of the most beautiful quality and top work too, both in childhood and later in life with my handsome price till his passing, and our children till it was time for them to grow and go.
Our parents hoped for four: two boys, two girls. I was born in 1947, brother in 1949, then the second boy, baptized Kevin, was lost in a preemie birth related to storm flooding, in 1951, and my sister born in 1953. Love of God and Man ruled and every factoid of insight came through the love filter - my brother wished he had a brother, but did not mind his adoring sisters like bookends, or guardian angels lest he 'dash his foot upon a stone'. As I have seen a lot of my life in several places now, I appreciate my parents' caring ways so much and more each year. They were truly wayyyy beyond their background limitations and put their gifts to work in this life, to world-class effect. I grieved when they passed away, but their lives rekindled, once the grief passed. They are wonderful and powerful spirits in my life. Scientifically , they live IN me and I choose the best of it, as I can and share it for the love.
In fact, my issue with my siblings is that, in such a powerful loving family circle, we siblings might never stand on our own alone well. But we do fine and lived far away from one another for years and now as older Americans, we are working to regaining that 'Washing the front porch" fun we enjoyed as children. "King of the Mountain" , Cowboys, Indians and Schoolmarms - I did not like the look of my cowgirl suit; the singing and praying and tag and "Fox and Geese" and a game called "Helping Mommy and Daddy" and spying for Christmas gifts; and more singing and dancing and food and eating and parties and more parties - and church and more church. The fun from those activities in childhood did their job and we like to cook up our part of it.
As far as self-actualization goes: the boys in our extended family of traditional ties seem to do better and we ladies working hard to win opportunities without losing our beautiful homelives. But most of the women CARE to engage in the great campaign for human rights for ALL so we seem to win our way well enough.
We- three sang in harmony for the most part, my sister and I shared a room in childhood and were great friends as young adults. Some special challenges in the midlife gave us lasting issues but we are at least enjoying "the good talk" on the subject. I need to read and talk with others and see how they are creating and enjoying their mature years, for ideas and truth.
I want to hear more... comment welcome.