Chicken and egg problem. In many countries the legacy of telecom access oligopoly led to an ISP oligopoly. If your ISP doesn't support it then you won't bother

Chicken and egg problem. In many countries the legacy of telecom access oligopoly led to an ISP oligopoly. If your ISP doesn't support it then you won't bother deploying since there's no IPv6 route. The ISPs won't deploy it until "there's customer demand" (even though there can be no customer demand until they turn it on - hardware and infrastructure have to come first before layers on top can be deployed). Switching to an ISP with IPv6 is usually not an option. Eyeball networks were waiting for the content networks to deploy and vice versa. Now that eyeball networks generally moved first the content networks say their anti-spam and anti-attack solutions don't have IPv6. Many IT pros have become used to and even attached to Network Address Translation and specific IPv4 addresses. Some have beliefs like reducing security attack surface requires disabling IPv6, NAT is a firewall, or they reflexively blame any network issue on IPv6. If the cryptocurrency bubble hadn't popped maybe there could have been a IPv6 coin that rewarded mining addresses. Mine the one correct address out of 2^128 that block and earn a IPv6coin (joke).