BTC is less expensive every year so long as its value is relative to its population of users and also available ways to spend it. In theory its way more valuable now then the retail opportunities of years ago, the nominal price rises inconsistently but generally every few years but its justified by the value of possible usage. I do generally go off the potential coming from a larger userbase being the most obvious easy comparative value vs other global assets.
No matter the price, BTC will still be valued more in the times to come, so why not consider the current price - the good one to buy more?
