it does affect the volatility but it is not the only reason and it definitely is not the biggest reason. in other words even if distribution of supply had another model the price would have still been moving in the same roller-coaster manner.

for example price didn't go up to the moon in 2017 because the reward was halved a year ago! it went up because some big countries like Japan adopted bitcoin as a currency and many other countries started having similar friendly regulations towards bitcoin. additionally we finally had a scaling solution for bitcoin be implemented. and like always because the media was talking about bitcoin nonstop! that was a process to speed up the demand and that caused the spike which would have happened even if reward was different.