I'd argue that there always must be something else at play in addition to greed. Greed is a given and the driver of the economy. Companies don't suddenly decide that maybe they should increase profits. So it's imperative to understand why they were able to increase profit margins without competition taking their market share. IMO that tells us what intervention is needed. The ideal market is companies at a constant knife fight with each other.

There is no competition! There is like three companies on the shelf - hawking 12 different "brands".

The mystery is why you can get away with it. Bezos famously said "your margin is my opportunity". Why is there no Jeffrey Bezos waiting to pounce on the opportunity?

What do you say that those left of centre are blaming inflation on then?

Supply shocks, increasing corporate profit margins (i.e. unnecessary price increases that don't reflect increased costs), long periods of free money (<3% interest rates)