Ipv6 is there for 20+ years, cgnat is needed coz the net grows kinda exponentially due to stuff like IoT/mobiles/m2m, and isp's need to provide users with the ability to talk ipv4 simply because the other side refuses to deploy v6 abilities. Do the math if they really care.
Also the servers itself hosting the gameserver probably already are dual stacked. But the gamecode itself misses the support.
Then there is the issue of you as isp not being able or daring to show a fist and simply saying: screw you. Because you are risking to loose customers.
And as long as the company's earn plenty of money using outdated code, they won't change it, coz that would imply spending money that won't flow into fancy buildings, fast cars and all that other useless luxury.
Kind regards,
Alexander Maassen
- Technical Maintenance Engineer Parkstad Support BV- Maintainer DroneBL- Peplink Certified Engineer
-------- Oorspronkelijk bericht --------Van: Mike Hammett <nanog@ics-il.net> Datum: 22-09-16 13:23 (GMT+01:00) Aan: Alexander Maassen <outsider@scarynet.org> Cc: NANOG <nanog@nanog.org> Onderwerp: Re: PlayStationNetwork blocking of CGNAT public addresses
If you told them they would have fewer NAT issues if they supported IPv6, they'd start to care. 
They know enough to hate NAT.