I think that that would be assuming BTC ever becomes the primary unit of account.

Good stores of value, which I think BTC is aiming towards being, have always had a capped supply/been disinflationary/deflationary.

Also, it is important to realize that BTC is not deflationary, but rather disinflationary - in the sense that the emission rate is positive, but slowing.

Besides, a lot of conventional economic theory have been written during times when fiat is dominating the world order. It is not representative of what could happen with BTC as the main currency.