People have said “IPv6 is the future” for about two decades now. It was “the future” 20 years ago and is “the future” now. When is the future? Nobody knows. But it’s not today.
Implementing IPv6 can be tricky because of compatibility problems with the longer addresses, different firewalling/vhost setup, different subnet routing, IP allocation, different packet formats, and so on.
And IPv6 has an unfortunate chicken and egg problem. Hosting providers don’t implement is because ISPs often don’t support it. And ISPs don’t implement IPv6 because most online services don’t support it. “But we’re running out of IPv4 addresses” is something people have said for decades now, yet still IPv6 is not gaining that much traction.
IPv6 support will probably have to be added at some point in the future. I haven’t discussed this with iFastNet yet, so I can only guess their ideas and motivations. But my guess is that they’re putting off implementing IPv6 due to the same chicken and egg problem, and they want to invest their effort into things with more obvious customer benefit.