There's a pretty big difference between "The show is basically set in the modern world except for one sci-fi hook that the show is about" (a group of clones are running around) vs "You're in a sci-fi future".

It's probably so that there was time for a new batch of clones to grow up (presumably played by Ritter), otherwise you'd have to retcon the series to say these clones were all out there while Clone Club was doing their thing and they never happened to find any of the Ritter Clones despite taking down/revealing all the organizations.

A near future setting has its difficulties though. It's easy to get a lot of stuff wrong with how the future looks and it could become dated very quickly (even while the show is airing, e.g. political changes in Europe or elsewhere) which is not the position a soft sci-fi show wants to be in.