I notice that most addon boards etc.. are available in kit form rather than sold as a completed unit.
As a completed unit (already assembled) I know that it would cost more the sell because of the expense of the time it takes to put it together, but I am a bit curious why there are not some exceptions.
For example, the ADA Fruit Pi Plate comes with connectors to hold the the RPi to the board and a Breadboard. It doesn't come with the cable or connector to connect the cable to the bread board. You can buy their Pi Cobbler which contains the cable and the "parts" to create a connection to the breadboard, but not a completed assembled one. So before you can do any real connections to the breadboard without soldered connections, you have to solder the connector first.
I know you can just use jumpers, but I thought the whole point of the breadboard system which uses jumpers is the do this without soldering.
While some of the fun is the soldering part, it seems to me that in a teaching environment, when using a breadboard which is designed for non-solder connections, it would make sense if there were a assembled version available. I can see a bunch of kids doing a lot with electronics without having to touch soldering irons, solder, possible burns and damage to the boards, clothes, equipment etc...
Is it just cost? or are there some regulations like RoHS that are holding that back.

