You are right about my spending a lot of time designing while not trekking. The reason for that is keeping journals has made it possible to achieve much greater success designing and building equipment.
You are wrong, at least in my case, about not finishing the job and using the equipment. True, there have been some depressing failures, but for every failure or two, there is a finished piece of gear that get used, sometimes for a decade or more.
Henry from TarpTent once talked about a 3 or 4 ounce difference in the same way, referring to such a weight difference as not amounting to more than a few inches of water in the bottom of a quart bottle.
But it is always possible to focus on one piece of a gear puzzle and minimize its weight. Unfortunately, there are many pieces, and they all add up. That is why the focus on weight has produced the very light packing weights we see today, weights that outside 'survival mode' were unheard of not too many years ago.
Many backpackers seem to be aware of this "whole is the sum of its parts" reality, especially the ones that have achieved very light packing weights without sacrificing safety and comfort.
Most if not all of the commenters on your thread seemed to be supportive, but also wanted to be honest. You're right about there being plenty of self-appointed experts on BPL (that's true many places), but after visiting the MYOG forum for a number of years, I've been impressed with many of the items people have built, even if there were flaws. Building good gear MYOG is enormously difficult, without the aid of sources for the best materials and design staff, the best tools, etc., found in the commercial world. (Still, we see in the case of the recent posts from a Sierra Designs guy that they aren't exactly the bees knees either.)
So please don't be too critical of the MYOG crowd. As passionate as we are about this, we've probably suffered enough already.