Adoption does not mean that people will store their life savings in bitcoin. It may simply mean that they use bitcoin financial services to conduct transactions when necessary, thus increasing the demand for money in circulation and thus increase the implied price.
Increasing implied prices would be an incentive to hoard, and would attract hoarders. It is already an observable phenomenon. They re-enforce each other in a feedback loop.
Probably an outcome of Gresham's law.
Yes, I simply restated it with the current dynamic as an example.