We can see here in this thread how inflation can be directly driven by expectations. Since you all believe that prices are going to go up, you decide you better buy now before that happens.
That increases demand, which increases the price. A self-fulfilling prophecy. And that's why the Fed will signal things like reducing quantitative easing and raising interest rates. They are trying to alter peoples' expectations for the future. Of course, we are in somewhat unprecedented territory right now. No matter what monetary or fiscal policy is right now, there's no escaping a serious, real, pandemic-driven supply chain problem, which in and of itself does drive prices higher as long as demand stays high, which it is. Demand needs to drop just a bit, and supply needs to go up, or else monetary and fiscal policy adjustments are only going to be able to do so much.
This is a tricky one because you could see the potential for an over-correction. Demand may drop and supply may increase, such that things would have leveled off. But then the Fed raises interest rates a couple of times, taking away the punch bowl, and triggers a mini- or full-blown recession. Being Fed chairman is not an easy job, that's for sure.
But one thing is for certain-- companies are always going to raise prices in response to high demand. Part of it is that they can get higher profits per unit sold, but part of it is also that they are actually trying to reduce demand. They don't want to be in a position where they are bumming people out by not being able to fulfill orders. They know if they bump up the price a bit then that can cool demand, and they can thereafter do a better job of meeting demand without having to further increase capacity and thereby incur other expenses-- hiring, facilities, equipment, etc.