Deflation in bitcoin is not caused by a collapse in demand, but by a predictably constrained supply. Now what would happen if people did start suddenly hoarding? I mean HODL is just a huge meme at this point but what if EVERYONE actually did that? What would things look like then?
Bitcoin is not deflationary.
With each block, new amount of bitcoin will be created to its circulation supply. It will only stop in 2140 when all 21M (20999999.9769
BTC) bitcoins are produced.
Controlled supplyWe can consider Bitcoin as deflationary if the amount of new created coins from block rewards is less than amount of lost bitcoins. I think we can only have it after 2140 when no more bitcoins will be added to its total supply but there will be people who lose their coins by losing private key, mnemonic seed.