My gripe is selling the SIG 1911 still
Difference in mindset.
While it may be possible that a person could be equally good and perform to a very high standard with many different action types and holster types and carry positions and calibers, most people will benefit from focusing on a single handgun carried in a particular holster and carried in a particular position. This will allow them to reach the point of "Unconscious Competence" and be able to react quickly and decisively to any threat to their life and get inside an opponents OODA loop even when they start behind the curve when attacked.
Running at 60% of a persons ability with 3 or 4 different weapons is not as good as being at 90% with a G26 or whichever type of weapon a person chooses to focus on.
Most people, average civilians in particular, don't get enough practice with their carry weapon in realistic defensive shooting. The mostly do slow fire accuracy at 7 yards.
Call me cocky if you want, I really don't care. I shoot weekly so maybe that's why, but I've mastered several of my guns and am extremely adequate with them all. Practice in general makes perfect.
You do some FAST drills with each of your mastered weapon types and see how you compare with some of the guys who focus on a single weapon type.
You might find out you are an undiscovered handgun phenom and become the next Dave Sevigny or Rob Leatham or Jerry Miculek but across multiple action types and even start your own shooting school.