Standard theory of evolution: organisms that spend energy on features that do not contribute to their fitness will be at a disadvantage in the long run compared to others of otherwise similar type that do not. The others will have more energy to devote to reproduction.
Citing notable research might help me better understand your claim; it is very possible that I'm missing something, but that's not how evolution works to my knowledge, adoption of substantially new genetic features is rapid, but refinements or removal of unrelated genetic code is slow if it is not impacted by the substantive mutations.
