Makes sense to me, the thing that matters is not total money but active money. Prices go up because there is the same amount of money, but sellers expect more,

Makes sense to me, the thing that matters is not total money but active money. Prices go up because there is the same amount of money, but sellers expect more, and buyers are used to paying more. This can continue by having their proportion of earnings/wealth spent increased which increases total liquid money supply, until they are at capacity (i.e. spending their whole income, selling off assets, etc). Basically the inverse of people being averse to spending and instead hoarding cash, leading to deflation as prices are lowered to tempt them into spending again.