I couldn't put the full title in the subject line due to character restrictions, but here is the full question:
If bitcoin was fully adopted into everyday life, why would it ever be used for day-to-day transactions if the general consensus was that the price would always appreciate?
After reading several posts on this forum many people seem to think that Bitcoin will always go up. If this were to be the case, why would people spend Bitcoin at all? In this theoretical time, wouldn't it just be a poor financial decision to do?
Or is it thought that in this future where there is widespread adoption the price would stop being so volatile and for the most part stabilize?
Your whole assumption is based on expectation so it's pointless what others think or what crypto investors think. If bitcoin is expected to rise then its gonna rise at some cost. Nothing in this world is free, it comes at great cost and if bitcoin is supposed to go upwards only then obviously this will take great deal of investment from the same users who are expecting the prices to go up. This means, there will be enforcement of mining farms running 24x7 to confirm our transactions, there will be non-ending trading fiesta live 24x7, big whales moving market up-down, creating that buzz for the crypto world and that very volatility which will give rise to new portfolio's.
The bitcoin adoption is really big thing. If bitcoin gets adopted throughout the globe, then it will change the current theory of yours. Let's not forget we are moving real $$ to buy the crypto in one world (fiat) and then transacting our bitcoin and alts in the other for various purposes. The driving force exists!