The problem with that argument is that labor prices and the prices of raw inputs to manufacturing have also increased, showing that it really is systemic inflation and not meer greed.
And the theory doesn't really make sense in the first place, as if greed is a new thing that corporations just discovered in the last year or so?
The idea of inflation is that purchasers competing among each other for the same basket of goods end up bidding up the price if they all have more money to spend.
That's exactly what we've been seeing.