I have 4 horses and a mule. I don't plan on "bugging out" at all for 99.9 % of situations. But If I do have to move, I can take them out the back pasture and be in the national forest in under 3 miles.
So, be sure and get a breeding pair and a plan to develop a herd for trading purposes. Given just a few pairs and some reasonable luck, you'll go from two to 5 or 10 in just a few seasons.
In one sense, yes it is bad for new horse owners -- but then again, horses tend to breed in nature without much help! I certainly would not recommend green horses get horses just for this purpose; I only mention it as it pertains to people who are making them part of survival plans. In that case, it's rather obvious that breeding population matters. Presumably you'd get training and know-how before the SHTF. If not, OJT from a book and an old-timer will suffice.