That's not how it works lmao. 1 BTC = 1 BTC things aren't going to get cheaper. The opposite would occur, things would get more expensive if the supply gets lost. So if there's only 1 million BTC then prices would get cooked for goods and services.
Discussion
The units can get divided smaller, we can already divide one Satoshi by a thousand on lightning, so the purchasing power of sats will increase