Originally Posted by
EEngr
Just a guess. But that might be the 'sweet spot' for flash memory price/performance. Memory manufacturers have no reason to serve the relatively tiny CVR market and stick to building the maximum size devices the market and technology will support.
Some CVR manufacturers might limit the capacity to match the spec in their firmware (to match the regulatory requirements). Others might just put in the current standard sized memory and let the customer use it all.
In addition, while these are most likely 'Commercial Off The Shelf' (COTS) components, they are specially qualified for the application - in this case high temp and high 'G' impacts - which isn't cheap.
So when the vendor finds a component that 'works', they are reluctant to use something else.