My work regularly brings me into contact with people who keep getting pets, despite relying on help from social services, food banks and their children's schools to provide the basics for their children. I'm not talking about people who have unexpectedly fallen on hard times. I'm talking about families who have always been skint and will ask me for a Food Bank voucher or tell me they have no money to put credit on their electric and then, in the same breath, mention they're off to pick up a new puppy when they've already got multiple pets at home.
Why do they do it? Humans are complex, so the reasons will be many and varied. Yes, in an ideal world everyone would be financially responsible but it's not quite as straightforward as some on this thread make out.
It is fair to say that some of the families I work with simply don't think about the financial implications of their decisions, about pets or anything else. They've never learned how to budget, they've been in debt their whole adult lives, always robbing Peter to pay Paul. But they've never known any different and everyone around them is the same way, so to them that's just 'normal' life. There's often a level of denial about how far up shit creek they actually are, or blind optimism that "something will turn up", which is probably a necessary coping mechanism when you spend your whole life lurching from one financial crisis to the next.
But some of the parents I work with don't have the capacity to make financially prudent decisions through absolutely no fault of their own because of cognition and learning difficulties or Mental Health issues, or both. They often have little in the way of support and are socially isolated, so their longing for the love and companionship of animals is understandable, although in some cases they are not equipped to care for them properly.
This is purely anecdotal, but over the years I've noticed that the women I've worked with who keep having more babies despite struggling to cope (not just financially but emotionally and practically) often do the same with pets. The thing these women have in common is trauma. Not just a single traumatic event but years and years of trauma, often going back to their own childhoods. They have often experienced DA from multiple partners. I think it's something about trying to fill a void, feeling chronically empty.
I think its easy to say people who are living in poverty just need to make better choices, but that's a massive oversimplification of complex issues that in some cases have been entrenched for generations.