Looks like they both have badges, so I'm guessing the owner(s?) allowed them to breed.
If the owner isn't a professional breeder or pet shop owner, what do they do with the children? They can't let them run into the wild.
In most fanons, these things pump kids too fast for any practical adoption events. Would anon "adopt" the kids to a loving home in the factory to be recycled as feed? It would be a clever way to let adults refresh while keeping population down.
I think the Marisa is a stray, that's why she's imagining them frolicking in the wild. Where Reimu is imagining her owner accepting the Marisa. The Marisa doesn't have a badge, I think her ribbon is just supposed to be messed up there.
That is an interesting take. I'm guessing the cycle would be something along the lines of: -Adults refresh -Kos are born -Adults are sent off to be recycled as feed -Kos grow up -Return to start
Seems reasonable. The children ARE cuter than the full-grown ones, and yukkuri WOULD be kind of worthless, cuz there's so damn many of them...keep them while they're cute and just get something new. They certainly breed fast enough for it.
The dumped ones would also die rapidly in the wild or on the streets so it's not TOO hazardous for the environment, but I'm assuming the owner doesn't care much about that anyway.