If their CGNAT would perform better, clients would not even notice a difference. I hardly doubt all that buisness clients (thinking of small non-IT buisinesses

If their CGNAT would perform better, clients would not even notice a difference. I hardly doubt all that buisness clients (thinking of small non-IT buisinesses such as coffee shops) require native IPv4. An ISP who cannot offer a proper IPv6+IPv4 internet access should not be refered to as an ISP. He supports IPv6<->IPv4 segregation, instead.