Raspberry Pi 500+ boasts a high-quality mechanical keyboard with removable keycaps and individually addressable RGB LEDs, an internal M.2 socket pre-fitted with a 256GB Raspberry Pi SSD, and 16GB of RAM.
400 and 500 case are identical E. It is not the space. But the fact that opening the case is not considered a user task.
The 500plus has bolts to open the case rather then the having to deal with breakable clips. The 400 and 500 case need a little more width and completelly new injection moulding to do that.
As I made clear in my post. What you and I are willing to do. Vs what a corporation is willing to sell as maintainable are different.SSD and storage in general has consumer expected requirement to be replaceable. Hence why every laptop etc has easy covers for upgrade.
Doing that requires a whole new case with now injection moulding machines and factory lines etc.