It can be kind of similar with humans too, if you think about it. Except, yukkuris are sadly much less capable of influencing their enviornment and have much less chance of getting better lives. I kind of feel for those kind of yukkuris actually.
Well there is the whole thing of not being smart enough to do productive things as well.
Remember just because they talk and have some notorious similar emotions to us that doesn't make them much different from average animals, so it's natural for a pet "animal" to have a notoriously better life than a stray/wild "animal", or at least the unlucky cases, some wilds do have good lives, and from time to time, strays as well.
though truth be told, i prefer to label them "monster fauna", not like it make them less prone to this situation, but it fits considering their magical animalistic nature.
I'm depressing to me. This Marisa reminds me of the surprisingly nice gutter yukkuri from Yukkuri in the City series. They and this Marisa deserved better.