How would the app become a killer app in the first place if a huge fraction of users can't use it? And my estimate is it probably takes years to roll out IPv6

How would the app become a killer app in the first place if a huge fraction of users can't use it? And my estimate is it probably takes years to roll out IPv6 on a network that isn't ready for it - how would the app remain a killer app until then and not be disrupted by someone willing to run a proxy server?