I have to agree with Shiavo and Kymbadina. Just because I don't have enough disposable income to write a check for a $3000 treatment tomorrow doesn't mean that I am a bad horse owner. Any vet that is worth using knows and understands that too. It's not that most the people who are broke just have horses for grins and giggles, most of us are broke because we have horses. Because we suddenly have to pay twice what we have been paying to have decent hay shipped in due to a drought; because last week, we figured out Sparky's lameness issue and now he needs $300 corrective shoeing to be comfortable; because a month ago, our friend's horse colicked and we knew they would need help with the vet bill so we chipped in what we could.
It isn't always so simple and black and white that "unless you are willing to dish out thousands to treat all your horses, you should sell them". There are other factors to consider and it isn't all about the idealogical viewpoint that you do whatever you have to and spend however much it takes to save their life, regardless of anything else. Because many of us have a tight budget, we have to be more practical about the decisions that we make. No, I would not spend thousands to save a horse's life if there was no chance of it recovering to live a pain free existence where it could still be productive. Not only do I have the injured horse to think about, I also have to think about the other animals at my house that depend on me.
I don't think they would be very understanding if I explained to them "Well, the reason you are eating crappy grass hay is because I had to choose whether to spend that $2000 on saving 28 year old Flash's life or having a load of quality alfalfa trucked in". IMHO, it would be much kinder and more realistic to make the very hard decision to end it's suffering rather than spend thousands, compromise the care of the rest of my horses, and put them through more pain of going through a lengthy and complicated surgery or treatment.
I might have a different tone if I had $100,000 in savings and the horse was a $35,000 show champion but the fact is, none of my horses are particularly spectacular at anything and no matter how much I love them, there are a million more out there exactly like them being born every day. If needed, yes, I could replace one of them. Not emotionally, of course, but for every day work? Absolutely. Some may think that makes me cold, it may be true, I don't know. What I do know is that not everyone has unlimited resources and sometimes we are required to make a difficult decision regarding the future of more than just 1 horse. Sometimes saving that 1 horse's future compromises the future of 5 other horses and 3 children.