Developing unconscious competence with one's chosen defensive weapon doesn't conflict with having conscious competence with a variety of different firearms.
In one case, the goal is to be able to use a firearm reflexively. To deploy it rapidly and skillfully without having to think about any of the details of how the gun works. In the other, it's merely being able to remember how various platforms work so that one doesn't have to experiment with the firearm, or examine it closely to determine where the safety is, which direction it should be moved to fire or safe the gun, etc.
I have a few carry guns, but I don't rotate them, I choose them based on what I can carry given the circumstances. In some cases, I can't conceal a full-sized firearm, so I have another smaller firearm that points the same for me and has the same manual of arms but that is easier to conceal. If my mode of dress is constrained even further, I have an even smaller handgun that points the same as my other two carry guns that I can conceal no matter what I'm wearing.
I don't see a problem with having multiple carry guns as long as they all point the same and operate very similarly. For example, I wouldn't want two carry guns, one of which was up for safe and the other one which was down for safe. I wouldn't want to have to consciously adjust to get a gun on target during the draw--I want it to come up with the sights already aligned on what I'm looking at.
If I ever need to use my carry gun, I want the actual manipulation of the firearm to happen without my having to think about it or adjust/compensate. I think that there will be other things going on to fully occupy my attention and to keep my decision making capability very busy.
Those are the things that are important to me.
I do think it's important to be able to run a variety of firearms, and if there were circumstances where I needed to employ another firearm that handled/operated/pointed differently than my carry gun, I would be somewhat handicapped if it differed significantly from my carry gun. Although I can run any common firearm competently, I don't expect to have the same level of reflexive skill with it. I just don't have the time and capability to develop unconscious competence with a variety of firearms that operate and point differently. Maybe some people do and that's great for them if they do.