Part of the reason body armour is becoming a standard is simply most cannot have a school without insurance, either to protect the school owner or the landlord, and the insurance industry is making use of body armour mandatory or suffering loss of insurance.
Then there are humanitarian concerns for student safety, being able to defend onself flat out is very different from getting wasted training.
I came from the pre safety gear days with very strong body contact and light taps to the head mandatory for scoring, but have gone through many layers of what works.
The best instructor I ever trained with, and the best 'sparrer' bar none I've ever experienced never included any sort of kumite within his classes, but his skills and his students came from superior drills and othe techniques.
After years of thought I moved my program away from a heavy sparring diet, and today only use it for advanced students where it makes sense in their training program. A far cry from the days students started sparring their first night.
It's interesting having the student spend years developing skills first actually makes for better sparring because they have technique that works.
But as sparring is such a minor aspect of where I see karate as going, it is only done in limited context.
bushi no te isshinryu
offering free instruction for 30 years