This summed it up pretty well. Owning a horse, at all, is a lot of work and a ton of money. As a teenager, it can be hard to balance your time at school and with friends and with your horse. I am a freshman at college (commuting to a local university cuts the cost in more than half) and I am just recently getting back into riding horses (after losing my mare about 7 years ago to cancer). I am lucky enough to have a family of horse lovers (and the land to keep my horses on) and my mom definitely helps me out when I need it. Every month you have to worry about feed, board (if you can't have them on your land), vet bills, farrier bills, the list goes on. You should definitely do research in your area before you commit to a horse. I am a firm believer in the idea that once you buy an animal, you make a life commitment to them.
I wouldn't say that I am spoiled because I have a horse as a teenager, or that I've never known hardship, I've worked my ass off to get where I am. I have a job working at a farm in my area where I get paid to feed/clean/train the horses, but I am also going to college full time and I get good grades. I pay for most of the expenses for my horses, luckily I have never had to make an emergency vet call, but I am prepared if I ever need to.
I bought my horse because I needed an escape. My dad is a verbally abusive alcoholic. Spending the time with my horses helps me escape that abuse and it makes me happy.
Until you meet someone in the situation, I wouldn't make such a general assumption. Hardships come in many forms.