I agree with
@Palomino and all listed points. Another thing I would like to add. What is the demand for a Morgan in your area. In other words, why would you want to buy a mare, breed her, wait nearly a year, then 6 more months to wean, training during that time, ......for what purpose? Not being a wise guy..... do you love the Morgan breed? Do you use a Morgan for riding, showing, or driving? Have you ever had a mare to foal? Any large animal to have young? A cow, horse, any large animal? Horses are much more "fragile" when it comes to foaling than a cow.... the time for a foal to be safely born is much shorter than a cow and your window to help if there is a problem is shorter.
Many mares will foal when you turn your back to go to the house for a quick trip to the bathroom.... many will foal out in the pasture when you are sure they are no wheres near to foaling.... but if there is a problem, you have little time to right a difficulty.
I bred Appaloosa's when there was a decent demand for them. There is more expense with them than ever with most cows. I had a market for a few foals and was able to sell a few. There is no market for horse meat in this country. There are no kill plants. So now there are many many horses with no place to go today. I am not suggesting that what you breed is only kill quality... but what I am saying there are many horses that don't have a "home" now, breeding and bringing more into the country will only add to the surplus.
As palomino said, most breeders are happy to break even/make their expenses. If you were actively showing, with a good reputation for having quality animals, and had a bloodline that would be in demand such as high quality quarter horses for cutting and reining, or warmbloods that are used often in jumping, cross country , steeple chasing, or something like that ; then I would say, maybe yes.... But to just buy a mare to breed with no plan down the road would be a big money pit for you in most instances.
The other thing, at least with a cow, sheep, anything, if it does not sell, or turn out, you can eat it. Sadly, horse meat is totally unacceptable as a food source in this country. I am not saying that there should be wholesale slaughter of horses, but there are some horses that should not be saved or bred or kept....the best place for many would be as a food source.... if only for dogs and cats and other carnivores.... there are alot of cows that have great personalities too...