The value in exiting providers is their reach; versign for example is deployed in practically every trusted root bundle. When GoDaddy wanted to enter the market, they bought Starfield who already had a root which was widely trusted and crossed that with their own.
The reason people will pay for you to compute a number based on a number they give you and your super secret number is that people trust what you’re doing with your super secret number. And that trust takes time.
Some history here. http://wiki.cacert.org/InclusionStatus And that's before root stores had to deal with Honest Achmed's Used Cars and Certificates.
cpach•1h ago
This makes me curious: Do you have a specific goal in mind?
https://github.com/mozilla/pkipolicy
https://www.ccadb.org/
https://cabforum.org/