@ vintage repairer , the vacuums they arent' allowed to retail will be shiped to another country and sold there. Patents are not world wide you have to take them out in any country you wish to sell your product in.
As for the insight looking like a sebo, in the same way that all 4x4's look the same and all semi trucks look the same. The insight is a answer to a customers need , customers want the design with those features so they make it so, Karcher , Ivac lindhuas , advance , nilfisk , wap , they all based there upright designs on the origional sebo from the 70's , twin motor , built in hose, then the single motors models came out and every one based there vacuums on that,
If you want to get technical , and Petty then Hoover should sue every manufacturer out there as all uprigh vacuums are based on their original idea of a suction motor and a beater bar with a handle for easy movement