The Metropolitan stopped production in the Spring of 1961 but dealers continued to market the remaining cars until Spring of the following year. I don't have both of these at hand to do a comparison, but I think it's safe to say that this is the same brochure as that produced in 1959 when the Series IV Metropolitan was introduced. They have different reference numbers.
Had they updated to the 1622cc engine and a 4 speed transmission, they may have been able to continue selling them. But it was never a sports car. The enclosed front wheels hindered manuverability considerably by limiting steering angle. If they had made modifications there, it would have helped. But BMC, makers of the Metropolitan, already had the Austin-Healey Sprite and MG Midget. Triumph had the Spitfire, and Sunbeam had the Alpine. The market for low-end British sports car was saturated. There was some similarity to what the Mustang would be, but that was a bigger car and was propelled by a huge list of available equipment.
While it didn't make sense for Austin to make them, I think a case could be made that AMC needed them. Being imported, they cost as much as a bigger American, but they might have been able to fight it out with the Corvair.