The 1911 was initially introduced into military services as a military design looking to create a very early version of how we are currently familiar with how interchangeable ar15 parts are. The military wanted the 1911 parts to be interchangeable regardless of manufacture. I believe they took parts from every manufacturer entering bid as a test randomized them all in a bucket, assembled them all in whatever random configuration of different manufacturer parts and fired them all. I believe several of those manufacturers tried to claim the copyright (if copyright is the correct term) on the 1911 design but they were all denied due to it originally being a military design.
Until recently the 1911 was predominantly used in us military service, however during that vague “recently” timeframe many of your non special task/force units changed over to various 9mm (Baretta, Taurus, etc, I believe I had a Taurus variant) due to 9mm being the NATO standard for that platform. So trying to keep the long story short, being still currently in service it is one of the most longest service lifespans for a firearm in the military, thus “most tactically proven statement” regardless of their claim to the design or how many are still actively in service.
Edit: also regardless of how tactically sound the caliber is, or magazine capacity etc etc etc I’m not trying to argue its better than other firearms but that it has had a really long service span in military and still not completely retired, even if it might be on the way out.