The fact that many today's advanced countries (France, Germany, UK, Netherlands, Belgium, Austria, Nordic countries, Japan, Australia, Canada, US...) are what they are dates back to centuries of more favourable and advantageous conditions or is it mostly results of more recent events?
Also, are trends reversable and such countries will eventually lose their spot (due to slowed growth in some of them), or is it the case that "they are there to stay"?
Not sure about what you mean by "best" and "dates back to centuries" Will hazard a guess and say No. The quality of life in 12th century China was much better than Europe of that era. 16th century America, Canada and Australia were not advanced societies in the terms you mention. Persia, Egypt and India once supported cultures that were probably the "best" of their time but don't appear on your list. Yes societies are born, mature, decline and die. Consider "the glory that was Rome" then visit contemporary Rome which in many aspect is a bit 3rd world by todays standards.