With Playmobil, they must be going after the mid Gen-Xers who grew up with Playmobil (which launched in 1974) in the 70s and 80s--and were the next generation (pun not intended) to discover TOS at at time when it was not only in heavy syndication, but the series was a major success on home video starting in the early 80s. It was everywhere, so for members of that end of Gen-Xers who grew up as TOS fans, the Playmobil 1701 might be right up their alley.
Oops, you’re totally correct - I totally didn’t consider those 80s kids who would have coincided with both. Partially because where I lived in the 80s Star Trek wasn’t aired in syndication from about 1980-1985, so my goofy brain thinks it wasn’t on the air for anyone those years.