From an accountant's point of view most, if not all, horses have to go in the liability column of the accounts. Just like adding an extension to your house, there is no guarantee that the cost of any improvements will be reflected in the value of the horse. Many of my clients have spent far more on training and equipment for their horses than the horse cost in the first place. This is especially true for native ponies some of which can be bought for under £100.
I used to have the view that competition compromises horses - the drive to win can make people very predatorial and can mean that horses are over worked when they are too young, they may be kept in a lot of the time and have to wear gadgets aimed at disguising symptoms rather than curing problems. On the other hand, I think many of our ordinary hacking horses can be compromised too - the cost of physiotherapy and the frustration of finding a decently fitting saddle often mean that things are deliberately overlooked until a horse starts shouting. Petra Perkins has got a sore back at the moment and I have had to take a deep breath before embarking on the long journey through physiotherapist, saddle fitter and then riding instructor. Petra cost me nothing in the first place but she has cost me quite a bit since!