I don't think it is realistic to try and bring regular cops up to that standard of discipline
Why is that? I can understand if you think there's a practical problem with doing so (but would still lament that), but I think that ideally "regular cops" should absolutely be held up to that same standard. I mean, look... these people are literally given life-and-death responsibility over the general populace. They should be held to a ridiculously high standard.
It is a practical problem. The military has an extremely long institutional memory and has perfected the process of mental conditioning over hundreds of years, to the point where 18 year olds can be given the power to kill and dropped into situations with little to no supervision - and it generally doesn't result in an x-rated version of Lord of the Flies. The methods that the military uses to accomplish this would not work for police without a costly tear down and slow rebuild. The list of methods is far too long to list here, but they include a culture of self policing enabled by a meaningful shared experience (basic redefinition of family), and a mythology that requires a carefully managed narrative of history (Gen MacArthur's farewell address at West Point is full of examples).
Even if it wasn't life or death, they still determine the outcome of your physical well being, future and livelihood. Giving them access to lethal force with practical impunity is the icing on the why-give-them-so-much-power cake.
Why is that? I can understand if you think there's a practical problem with doing so (but would still lament that), but I think that ideally "regular cops" should absolutely be held up to that same standard. I mean, look... these people are literally given life-and-death responsibility over the general populace. They should be held to a ridiculously high standard.