I'm puzzled by how America ended up with this "lone-wolf" nuclear family mentality where families move away from parents and insist on going it alone. Go west

I'm puzzled by how America ended up with this "lone-wolf" nuclear family mentality where families move away from parents and insist on going it alone. Go west young man was not just a saying but part of America. Look at post WWII information on families moving to California for example.