There is also the corporate market. The big corporates (and there are many, with a lot of flyers, who are not price sensitive) often have policies on corporate travel - as in, duty of care to those employees they send travelling for the job.
I've told the story before of a large gold mining company, with operations in many third world countries who even in the 1990s had a corporate airline safety guy whose job it was to individually assess the airlines (with a focus on the small domestic airlines of said countries) for their safety characteristics. He dug deep. In one prominent mining country, he judged the commercial services not good enough so the company had their own 15 seater based there to ferry people about.
When I travelled around the Middle East for work, also in the 1990s, the large Australian mining company I worked for had a list of airlines and airports that I was not permitted to fly on/to.
Today, it would be hard for a large corporate to resist using a reputable commercial 'airline safety assessor', again as part of their duty of care to their oft-travelling employees.
I'm sure such services exist today, but probably so specialised and expensive that they don't enter the general market.
Although flying is very safe, there is a very risk-adverse portion of any market that is willing to pay to dot another i .