I completely agree. Sure stainless would be amazing. But if I'm going to settle for plastic, I want some other perk.
I am still blown away that no one makes a 6.5 - 7 gallon PET carboy. They would get rich off me alone.
Who brews 5 gallons in primary anyway? Almost nobody. My 6 gallon PET carboys are nice, but at 5.25 - 5.5 gallons, there's always a ton of blowoff, and often a mess that my blowoff container can't hold.
Make that a 7 gallon PET carboy with a wide mouth and you'll sell more than you can make. With all the innovation in homebrewing the last 5-10 years, I am shocked this doesn't exist.