what does the sentence mean?

Growing up in the 50s was a time of innocence and fun. I can look back and see that I have enjoyed a period blesed, if you will. with blandess. In fact, most of 20th century America is remarkable for the positive things it produced---the Industrial Revolution, television, computers and enormaous advancements in medicine and information access...
But now ,knowing as we do that the onl thing constant in life is change, I am beginnig to understand that moving from the Renaissance to the Vicotrian era was predictable. SO ,too, is the sewll of political and social change I feel engulfing our world today ,and I am beginning to be worried for my children and grandchildren. Like our relations or our golf game, the minute we begin to feel really comfortable with them is the very moment the downturn begins. It is built into the system and Ibelieve it is a microcosm of how our universe works...
what do the two paragraphs mean. in particular the sentence"like....,the downturn begins" and what the "them " refers to in the sentence?
thanks