Peacocks in the wild are often caught by their long tails and killed. They aren’t the only ones. The story repeats with male African Long Tailed Widowbirds. So the question goes: how does an evolutionary process that is meant to ensure fitness continue to favor a trait so adverse to survival?
The answer lies in genetics. At some point a gene that strongly correlated with survival was linked to another gene which was not. Imagine a gene that provided valuable disease prevention was situated adjacent to a gene that produced longer tails. Long tailed members of the species would survive more in spite of, not because of, their long tails.
When this happens you end up selecting for one more trait through sexual selection. It is the children of females who preferred mates with long tails who survive. So over time the species gets widespread deployment of a valuable gene but at the cost of a propensity for long tails and sexual selection that favors them.
In the case of the African Long Tailed Widowbird mentioned above, this selection process is demonstrable in a lab. Take otherwise identical males and give one of them tail extensions and the females go for him every time. I suspect a predator would do the same. This is often called Runaway Selection.
I have found many parallels to this process in marketplaces far away from the wild. Let us consider consumer electronics, for example. Once a new product gains traction with certain specs the competition often heats up around those “speeds and feeds.” We get processors with more megahertz even though bus speed might be more important for many applications. We get cameras with more megapixels when it may be preferable to have larger pixels instead.
One of the big challenges with success is that we don’t always know what contributed to it. We often misattribute success to one feature when another is more important. Only when you take a risk and break with the status quo do you discover the value of individual features. In a way success can be paralyzing because we can be afraid to change anything for fear of losing it. As Warren Buffet once quipped, “only when the tide goes out do you discover who has been swimming naked.”
In fact I even see something analogous in my own personal development. Early in my career I was successful with a very aggressive personal style. As I grew more senior my style was increasingly disqualifying for the types of roles I wanted to take. It took Sheryl Sandberg pulling me aside and telling me, “You think you are successful because of your style. You aren’t. You are successful in spite of it,” for me to understand that they were separable. I had been swimming without trunks and I was lucky to have a mentor like Sheryl to let me know before the water receded.