Why not? Your floor is the base cost of the BOM. Since they absolutely and pathetically have to prioritize shareholder value there is strong impetus to drive prices up or extract additional value some other way. Remember if you're not showing cancerous levels of growth you are dying, if not worthless!

The only time prices ever come down is when one tries to undercut the other, or they feel they can make more money by lowering them. This rarely happens in any permanent or consistent fashion, barring exceptional circumstances or a collapse in demand.

Add in inflationary pressure, and exec's pathetic desire to be cool and copy what their competitors are doing (who cares why? AcmeCo has it, we need to have it to!!!) and you don't even need a price cartel because everyone is making the same sad little moves independently.

The conspiracy aspect is absolutely a red herring. Nobody is that smart, thankfully. This is all supposedly rational actors acting in supposedly rational self-interest. AKA "Market forces"