I don't think that follows as well as you think.

If the primary goal is survival based primarily on efficient use of energy. A lot of evolution is about organisms becoming more efficient by adapting to their environment. So then keeping unnecessary junk around is inefficient and we would expect orgasms that lose to would benefit and out breed the others.

Having our optic nerve run right through our retina producing a blind spot in order to capture an upside down and backwards image is pretty inefficient too. Evolution doesn't maximize efficiency, it maximizes good-enough-to-reproduce-ity.

Better adapted organisms are just that - better. Not perfect, or free of inefficiencies. And even a perfectly adapted organism might not be as good at adapting to changes in the very long term compared to one with "junk" DNA. Also, does unused junk in the DNA really hurt energy efficiency?