We have a dog and had cats. I have pet friends. They are free to leave as they wish. The cat left and then came back with kids. Then they left but some will come back and go. The dog is still there, doesn't seem so enthusiastic about going too far from the house.
And yes. I think slaving/caging an animal is brutal. But many animals will happily have your company.
I have an anecdote that I personally witnessed a few years ago, which makes your claim way more probable than some here would suspect.
I was visiting Bay Area a year before COVID and stopped by in Berkeley for something, iirc was getting brunch with friends. The first thing I see after parking is a full street closure and a large crowd that looked like it was marching down the street, with people holding banners, drumming, chanting slogans, etc.
Out of curiosity, I decided to check what it was about. As you have probably guessed by now, "pet ownership is slavery" was the theme (one of the banners in the front was saying exactly that).
I mean the obvious parallel to slavery, they are property owned by somebody who are not truly free to leave and have been bred to the point of dependence, are regularly neutered, are leashed regardless of need, they are commonly fed kibble produced from waste not fit for human consumption at rendering plants, and so on.
I'm not saying there couldn't be I don't know, a pet owner who took them in off the street or from a shelter, nursed them back to health, and are lifetime companions in a consensual idealised relationship, with the ownership mostly being a legal technicality. Yet there is an ethically dubious side to pet ownership which I could imagine getting the entire institution framed in a negative light in the distant future.
I imagine in the year 3000 there might be a future where schoolchildren will be shown holograms of rendering plants and told by the teacher "And this is what they fed the animals" and then a Labrador Retriever will have an AI write an essay which states that "the ownership or consumption of any animals, is fundamentally a crime against animal rights".
And yes. I think slaving/caging an animal is brutal. But many animals will happily have your company.