I second, third and fourth everyone else. Those are all good reasons.
DIYers also keep the manufacturers and their mouthpieces (Backpacker Mag) honest - ish. We tend to know what light weight and performance really are.
The industry always tends to inch the weight up. Weight creep is inevitable as manufacturers respond to returns due to failure. It happens every time UL comes around - which has happened 4 times since I have been paying attention...like since the 1950s. The internet may keep UL alive instead of fading out until the next Ray Jardine or Gerry Cunningham pops up.
DIYers do something else - They keep it simple. Eschue complexification!