When Sony first started cranking out camera sensors that worked well (enough) at high ISOs many who were engaged in building their photographic businesses rejoiced. They concluded that they would no longer have to learn to apply enough light to their subjects to prevent objectionable noise from creeping into their files. Practicing their craft as "available light" experts they would no longer be questioned about the sparkly and speckle-y noise in the photographs they were delivering to their clients.
The remedy to noise, for photographers who could not or would not light, was to crank up the ISO in the camera menu and then wash out the photographic detail (which included noise) in post production, with canned noise reduction programs. This led to an epidemic of plastic looking skin tones and images with less detail than had been available in correctly exposed files from 2-4 megapixel cameras long since abandoned.
As the economy recovered fully from the last recession and clients once again started investing more time, money and attention to their marketing content a funny thing happened; clients started demanding that their photographers know how to light images. It is not good enough anymore just to get an image that could be post processed into submission, now it is becoming mandatory to use lighting correctly.
Photographers can (and should) use lights to create depth in images, raise the overall technical quality and sharpness in images, and to create images on locations, on demand, that have the same kind of quality metrics as controlled studio work. The re-introduction of good lighting as a primary function of photographers points to a small renaissence in commercial work; both in still photography and video.
The current mark of competence in image making is the ability to light well. To enhance one's subjects and create looks and styles that are repeatable and not just subject to luck. Every project is different, that's why mastery of lighting requires looking beyond a handful of formulas. One job may require huge, directional soft lights while another might require the fine edge of a hard spot light. The project and the imaging goal should drive the lighting and not the other way around.
If you want to have repeatable photographic results and repeatable client engagements I highly recommend gaining a comprehensive understanding of how to light. Even if you wish to remain an "available light" photographer understanding the theory behind good lighting can't be a bad thing.
The nice thing about having lights and knowledge is that when the sun sets you can still do work that is financially rewarding. I'll leave discussions about the art to someone with an MFA.