There is much more to the rise and fall of the Singer Manufacturing Company. There is a great book by Jack Buckman titled "Unravelling The Threads: The life, death and resurrection of the Singer company".
At first, the 4 principal patent holders formed a patent pool, preventing anyone else from entering the market. This is illegal today, it's effectively a cartel. As they innovated, the founding companies created new patents, keeping a grip on the market.
Then came the end of World War 2. In order to prevent the sort of economic collapse that lead to the war in the first place, as part of a redevelopment initiative, Germany was given car manufacturing and Japan was given sewing machines. Both countries did well out of it. This is why many of the early Japanese sewing machines look like Singers.
Then came mass consumerism resulting in a much reduced demand for sewing machines. Diversified corporate culture (conglomeration) axeing the least profitable product lines. Bad CEOs and a hostile takeover in the 80s, breaking the company into little pieces. Some of the pieces were picked up by the newly formed Singer company that we know today, which due to market contraction, also owns Pfaff and Husqvarna Viking.
Very little of this is mentioned in this in the programme, I guess they focus on the Kilbowie part of it. I highly recommend the book.