Adoption is a gradual process. It will organically increase the price. But dont forget that the fiat price of bitcoin has nothing to do with its intrinsic price, like 1btc will always be 1btc.

Engagement is a one off phenomena, where suddenly you see a rise in traffic. This is temporary and will always lead to short term rise or fall of market price.

Demand is currently low because the places to spend bitcoin are less and supply is reducing so deflation is happening in price.