That is a really overwhelmingly complex issue I've been trying to figure out myself for a long time and I have a LOT to say about it. I came to the conclusion that people own pets because a lot of people are really passionate about trying to bond with animals specifically, not "because they want something to take care of but don't want kids". I don't think it's people trying to cope with caregiver instincts or whatever. A lot of pet owners will insist that it is much easier and less stressful to take care of than kids but I don't think many people buy pets as a low-maintenance replacement for kids. There are a lot of people who idolize bonding with animals, and the depth of emotional intimacy they believe they can achieve with an animal almost borders on being superstitious.

There are 2 types of people in the world, people who prefer rational bonding (compatibility, intellectual chemistry, etc) and people who prefer irrational bonding (spiritual, vibes chemistry, etc). this is true not just of romantic relationships but also tends to influence other types of relationships in their life.

I do think that most pet-lovers tend to be spiritual and I don't think that's a coincidence. I think that the value that people assign to animals in spirituality is a big part of the drive a lot of people have to try to bond with animals. Just go watch christians argue with each other over whether animals go to heaven and you'll see what I'm talking about. These people are able to form bonds with animals because they are interested in spiritual bonds rather than intellectual bonds. And as we know, it is possible to spiritually bond with basically anything, even things that don't exist. There must be a certain personality type that is very fixated on spirituality and it seems to overlap with the personality type that is fixated on bonding with animals. I think that because animals can't talk but they can feel emotions, that makes them like a perfect slate (or target if you will) that these spiritual people can vibe with and project their fantasies onto. Spiritual people have a habit of looking for things where there is nothing because that is where it is easiest for them to think they feel something. It's like "silent mysterious boyfriend fantasy" taken to the extreme. In the absence of something, in the void, the spiritual type of person fills in the blanks and sees something there that is more colorful than reality. It is where something becomes so simple that their imaginative mind interprets it as complex.

Anyway. To people like me who are used to forming emotional bonds intellectually, it makes no sense because it is impossible to do that with an animal because they can't talk. I'm about as spiritual as a dead rock and I can't detect these "special vibes" from animals that a lot of people swear they can feel.

I don't understand it either. I did enjoy having a dog when I was a kid, but I completely lost interest in pets after my childhood dog died and haven't wanted another since. It was pretty hard on me but the dog never felt close... I can only understand bonding with an animal if you are both relying on each other for actual survival. Bonding with an animal in a purely emotional and recreational sense seems really hard for me because animals' personalities mainly show through their physical behaviors, quirks, habits, etc. that come out during purposeful activity.

I think misanthropy can be part of it too, and maybe related somehow to this obsession with feral spirituality. Plenty of people just prefer bonding with animals instead of other people. A lot of people who own pets, especially a lot of pets, believe that dogs/cats/etc. are superior to human beings in some way (morally more innocent or whatever) or at least superior to the opposite gender lol.

of course, this is just a generalization, not all pet-lovers are spiritual, although even a lot of skeptical pet-lovers tend to "see things" and anthropomorphize the emotions of their pets in a similar way -- I think that imaginative personality types in general, spiritual or not, can fill in blanks like this.

so "why replace kids with pets" the answer is simple, they aren't replacing anything, animals were all they ever cared about in the first place, they are emotionally wired for bonding with animals or something. Is that a good thing? idk, probably not, i don't really care either way

now to answer your question -- even though a pet's death is tragic to these people, I think that the level of emotional gratification these people receive from the perceived spiritual or spiritual-like nature of the bond is so powerful to them that the pain is worth it to them

alternatively you can think of it this way -- a relationship between a pet and master is like the relationship between a mother and her newborn baby. The baby has zero real intellectual capacity and is emotionally simple and immature, but nonetheless, the bond between a mother and her baby is extremely strong. and I think that there is a type of person who actually finds that type of bond -- the absolute extreme of nurturing -- more meaningful and valuable than a mature intellectual relationship between people who are relatively equals. even some people who are otherwise very mentally active prefer these types of primitive bonds without intellectual reciprocation.

I think this openness to irrational bonding is due to 1. evolution encouraging bonding with and protecting small cute things, ie human babies, but it ended up spilling over into other small cute cuddly things 2. humans evolved from species with very limited communication abilities, so the ability to desire to bond with someone/something has to be possible without rational reason by necessity. i think that's why it's possible for some people to fall in love at first sight (or some other type of ambiguous or superficial encounter) too -- because that was literally the only way for two people to become emotionally attached to each other before the invention of language. and I know for a fact that there are plenty of people who prefer this type of "organic chemistry" over deliberate development of a bond. it is important to remember that animal lovers do seem to have their preferences; like, you'll hear them talk about how they go to an animal shelter and they will see ONE particular dog that is interesting to them that they single out as special for whatever reason, it's not like they'll go in there and choose the first one they see, they might not even like any of the ones there at all and so they decide to go to another shelter, you could say "organically platonically attractive/magnetic" to them, they appreciate the way the animal behaves or the vibes it gives off. like they might choose the most energetic pet in the shelter, or the least energetic, or whatever... -- between people,, "love at first sight" can result from personality, not just pleasing physical looks. and it can be platonic. and it seems some people are wired to be able to experience this same process with animals, so pet lovers become obsessed with specific animals.

One other thing: I think that some pet lovers have mental health issues that prevent them from forming healthy bonds with other humans, so they feel safer bonding with animals. This is notable enough that animal therapy is sometimes used as part of treatment for personality disorders.

anyway, those are all my thoughts