.30 Super carry? Oh yeah, you must mean the French long 7.65. That shit was dead before before it ever got off the ground. The must have found the guy that came up with the .45 GAP cartridge and asked him if he had any more great ideas.
The 100,000 firearms engineers employed over the years at a thousand firearm and ammo companies have spent trillions coming up with the most lethal projectile an auto loading pistol will work with. Considering the market is basically composed of 4 cartridges for full sized pistols, 9mm, 45ACP, .40S&W and the 10mm; 9mm and 45 are over 100 years old, the 40 and 10mm were developed in the mid 80's IIRC. The idea someone can engineer a "better" functional round without some giant leap forward in metallurgy, combustible powders or something we have yet to develop it's still the same cartridges. Just ask a Glock sales rep how well those .45GAP guns sold