At the end of the day, though, at-will employee or not, who cares why you lost your job? You still lost it. Being let go because of infrastructure changes is more or less the same as being let go because you s**t in the lunch room fridge. Maybe the first instance will net you a better reference for later on, but that's all.
You don't want to focus on why you were fired, because it does nothing for you. Were you persecuted by an a*****e manager who had it in for you until they finally broke you? That sucks balls too, but forget it. Unless they framed you or some s**t. In that case, sue them six ways from Sunday. But assuming your firing wasn't illegal, just let it go. That's the best way to move into a new job. The bitterness, anxiety, and fear from losing your job makes you kind of weak and jittery and not in a good head space to find new work, which is what you need to do. Best to pretend you quit because you realized your old job was holding you back from becoming El Sexorcismo Royale, the world's foremost paranormal Mexican wrestler / sex idol.
One of these people is Cracked Editor Adam Tod Brown. The other is El Sexorcismo.