I've found that the small primer .45 AUTO brass is the brainchild of several of the companies who wanted to make non-toxic .45 practice ammo for police departments (who often shoot on poorly ventilated indoor ranges, and buy the vast majority of non-toxic pistol ammo). But, they were having a HARD time making non-toxic large primers - they just had lousy reliability. So, someone got a real stupid idea to go against the 100 year old SAAMI, mutually-agreed upon, shooting industry guidelines that .45 AUTO needs to be large pistol primed, and started making small primer pockets to hold the non-toxic small pistol primers that were easier to make reliable than the large primer size.
So, it was a combination of errors. PD's which would not upgrade their ranges with suitable ventilation to meet OSHA standards, government entities that refused funding to upgrade local departments and larger ranges to meet current air quality standards, and companies making primers who still have not figured out how to make non-toxic large pistol primers reliably. But if someone has more recent intelligence on this situation, I'd like to hear it. GJ