I have purchased two horses and found one - none lived more than 10 minutes. the one found, lasted about 100 yards before a pack of wolves killed him.
I will not buy any more and keeping them alive to serve their purpose should be paramount to their place in the game. If they like the way it is now, then give us an option to turn the horse into a non-target.
I can't even express how frustrating it is, having to babysit all the time.