Exophase
Nothing good will ever come of Exophase.
20EUR in a single part cost with production failure rates, board population fees, markup to cover returns, advertising, profit winds up being a 50EUR single part by the time the device sells retail.
Why would these things scale with the cost of the part? The bigger eMMCs are not more expensive to populate if they're the same pinout, and if this is even being discussed as an option then they'd better be. It also doesn't increase the cost of advertising. The cost of failure would also include a lot of non-proportional expenses like scrapping the whole CPU board or having to rework a new eMMC chip. But I doubt the failure rate is that high.
I just don't see how a fixed 250% rule of thumb makes sense.