A deflationary currency is designed to be hoarded, but it does not follow that coins will never be spent. Day-to-day transactions will still occur and will still require currency to perform those transactions. Assuming higher future adoption rates as the currency matures, it will increase pressure to both hoard and to spend. The question that needs to be addressed is whether hoarding and spending will both increase at comparable rates creating an equilibrium.

I would suggest that both working in tandem will continue to drive prices up in the long term. Working against this is the creation of new coins. I have not run any in-depth calculations on this but my gut tells me that adoption is currently creating a demand for coins to hoard and coins to spend that exceeds what is being provided by the current pool and the coins being created. If continued adoption rates keep their growth slopes then astronomical btc values are inevitable. If the rate of adoption reaches critical mass and goes exponential and becomes widespread, I think even the wildest projections will look puny. But that is a big pile of ifs stacked on a shaky foundation to begin with.

Edit: Currently btc are being hoarded and fiat is being spent. This is an important dynamic to understand.