I met Marion Olivier, "Miss Toupie", the owner of Toupie-Shop, this year at the Marines Festival (I cannot believe it was this year, just before covid: it feels like ages ago!). On her site she says her passion for tops started in adolescence when she had skirts that turned (?). She also says that she feels she was "born a living top"
Toupie-Shop is only about six years old while Kreiselparadies has been going for about 2 decades. The German site was also started by a woman, Monika Scharmann from the city of Esens.
There used to be another very good French shop, Les Trésors d'Agui, but unfortunately seems to have disappeared. There also used to be a similar but smaller site in the US, The Color of Life. I bought several unusual tops from there, but the owner had a progressive health issue and finally had to close.