The facts are that toward the end of its life here in the US, the Swift and Metro had terrible sales... gas was inexpensive and the full ascent of larger vehicles had heavy momentum.
I had been curious about this same thing, and since I purchased my Metro, I did a little research and came up with the highlighted info below, which I added to the
Wikipedia article on the Suzuki Cultus.
If you are interested in the sources material, scroll down to the last section of the Wikipedia article, on MANUFACTURING, and you can click on the original source articles for the information here:
While at its peak, Canadian Swift/Metro/Firefly production reached more than 100,000 vehicles a year, the number fell to just 32,000 in 2000. In response to the waning popularity of smaller automobiles in the North American markets, Chevrolet/Geo sold only 55,600 Metros in 1997, off from 88,700 the year before. In a 2004 Autoweek article, Osamu Suzuki, chairman of Suzuki, called CAMI "a fishbone in my throat" because of its low production.