TL;DR: economists are still stuck in the idea of the market as a perfect force for reaching optimal outcomes. They're ignoring the simple fact that businesses are putting prices up purely to increase profits. And that they can do this because the economic ideal of perfect competition (where many small firms compete with near-identical products) does not exist. We have a small number of very powerful businesses—oligopolies—in nearly every market for consumer-facing goods.
This is incorrect. Yes, greed exists, but it always exists. Even in classical capitalist economics, inflation comes when supply can't keep up with demand. Fiat currencies floating globally, rampant money printing, global shortages and supply chain issues plus corporate greed starts to show a clearer picture