The issue with applying an evolutionary metaphor to programming languages is that Natural Selection will thins a population by culling based on some environment

The issue with applying an evolutionary metaphor to programming languages is that Natural Selection will thins a population by culling based on some environmental event, which means that what one might rationally consider to be "fittest" is not what will be selected. So, the language may be well-strucuted, concise, extensible, etc. but natural selection may depend, for example, on availability for mobile platforms. In which case, languages that flourish on mobile platforms (e.g. browser-resident JavaScript) will survive that measure of "fitness". The same is true in biology. What may seem well-formed, robust, and inevitable is meaningless to the process of natural selection. Nature randomly and arbitrarily chooses what those species that are fittest. People too often mistake "survival of the fittest" to mean "survival of the most beautiful" or "survival of the most logical" because they consider existing species as fit by applying post hoc ergo propter hoc logic.