I sometimes hear the claim that innovation in the physical world has stagnated since around 1970. More specifically, chapter 1 of The Rise and Fall of American Growth by Robert J Gordon claims that there has been basically no innovation in clothing other than changes in fashion. This is somewhat contrary to my intuition (although I definitely believe that innovation in the 50 years before 1970 was greater that in the 50 years after), and price of insulation seems like a relatively objective metric for this.
My favourite type of response would be time series data of clo per inflation-adjusted dollar, but I'd also appreciate people's subjective experience of this.
Archive.org seems to me like the most straightforward way to handle cases like this: https://web.archive.org/web/20190415082549/https://www.times-news.com/cnhi_network/how-those-plush-easter-bunnies-got-so-cuddly/article_8e6a93c7-fbe4-5735-9d94-9426f0b3d164.html