It was not uncommon to have vermin-infested mattresses, even new off the production lines. Organic mattresses fillings of the time were subject to all sorts of attack by bugs, bacteria, and mildew. Boxsprings with ticking covers were still new selling at a rate of about one to every 15 mattresses. Business was great, but you know what happened in 1929. Bedding is sensitive to economic changes.
People can easily delay replacing their bedding a few more years.
Even today, on average, people only replace their bedding every 12.5 years. Cotton mattresses were popular even into the 1950's and 1960's. Cotton would mildew easily in hot humid climates before the advent of air conditioning. Cotton mattresses differentiate themselves in price points by using combinations of raw cotton and cotton felt. Cotton felt is cotton that is run through a garnet machine which combs the cotton into a fine and fully layer.