My 10 cents worth. Everything that the trike consists of must be propelled either by motor, your legs or gravity. It must also be lifted at some time if you plan to load it onto a trailer or into a vehicle. We are not all built the same with the same strength and ageing slowly takes it away from us.
If one had plenty of resources - staff, engineers, time, money, manufacturing and testing equipment - the very things that commercial manufacturers might have and charge you for, one could use them to shave every little bit of unnecessary mass to make the lightest trike possible. One could even calculate how much propulsion energy one could also save. All that adds cost and time to the build and you have to wait longer for the joy of riding. Then you load the trike up with bits and pieces that you think are necessary and enhance the riding experience such as tools, survival gear, etc. Extra mass means if you want to travel as fast as the lighter guys, you are going to have to work at it. Is there any great hurry to get there? I would shudder to think what my Warrior, and its add-ons, weighs in full flight. I don't really care as it is doing what I personally want it to. I might weigh it one day and then keep it a secret.
The new eLecTricks build does have some consideration for unnecessary mass but it still has to do what I want it to. Lessons learned during one's "building career" modifies our individual build approach. Then, we might become the experts that can set up a business with all the resources previously mentioned but I think too much time may have passed by. I think I know what I would do if I was able to have a re-run. There are many, many, trikes to be built.
Using what you have on hand (read saving costs) could also cause the build mass to blow out, but that's the way we do things, because we can, in saving the considerable add -on costs of commercial builds. If you want the lightest, you need to buy one.
If you make your first trike and it turns out to be what you think is a little too heavy, your second trike will probably be approached with mass conservation in mind. In the meantime, you have your first one to ride during the protracted build of what you think will be a lighter one.