This site has profiled various technologies that have a possibility of having very disruptive capabilities.
If those technologies interact for more rapid dissemination then people be even less ready.
The normal technology adoption cycle which takes years to decades for something new to scale up would normally provide some time for acclimation. People still have trouble keeping up with the normal technology adoption cycle.
The starting point for most people will be if/when there are some new radical technologies that shock the majority of people who do not believe in accelerating or radical technology.
This will be the point when those who have contemplating and planning will have the first opening to really affect policy.
Likely this will have to happen in multiple areas and it needs to be an in your face kind of radical change.
We could get the capability to extend lives by 5-40 years with sirtuins, gene therapy and other procedures and methods. (Genescient, SENS).
These would be powerful changes but deniable ones for decades.
Rejuvenation or regeneration are the kind of in your face : we are in a new world kind of change.
Space and Energy Technology.
Successful nuclear fusion or one of the radical energy technologies like low energy nuclear reactions could be a shock the world kind of situation.
What are the Factors
Psychological impact on technology doubters and ideally impact on day to day life.
Significant market penetration within a few years.