Depends.
Nothing 'wrong' with being a '1-gun' fellow if that suits you and your perceived needs. I started out that way, myself.
Did essentially the same thing in the martial arts, at first, too.
Nowadays I choose an off-duty weapon for a number of reasons ...
Planned activities while being armed, anticipated potential circumstances, clothing choice (mine or dictated by the circumstances, such as weather) preferred carry methods for given situations, destination & method of travel, time planned away from home and support, personal comfort ... and yes, sometimes simply because of a personal inclination to choose a particular weapon.
Over the years my common choices have become smaller & lighter. I grew tired of always carrying a full-size weapon, especially a heavy one, as the years marched on in my LE career.
I'm sure I could 'make do' with owning just one type of hammer, or one pocket knife, but some seem to offer advantages over others depending on the circumstances.
When I retire and my 'easy' access to a non-public range ... including targets and an ammunition inventory ... changes, I can see this affecting my continued training and the overall frequency of my practice to some extent. I'll probably choose to cut back on the amount of my practice and the number of weapons with which I practice. This will likely influence how I choose my commonly carried retirement weapon(s) to a reasonable degree.
I imagine I'll always have a few J-frames on hand, being a long-time revolver shooter, and I've developed a practiced familiarity and reasonable skill level with some semiauto pistols over the years, as well.
Based upon my perceived needs and personal experience I see no 'need' to limit myself beyond a reasonable balance of common sense, skills maintenance and the luxury of individual choice ... and any restrictions I may encounter elsewhere once I retire and have to qualify under another agency's requirements, of course.
It doesn't cause me a second's worth of thought whenever I encounter someone who prefers to limit themselves to either one specific handgun or even one specific platform. If it works for them, it works for them. Their business.
I don't expect them to bother themselves with my personal choices and philosophies, either.
I might even decide I once again want to own and ride more than one type of motorcycle, too.
Matter of fact, I'm seriously thinking about cutting back on the cigars and trying a pipe.