Then again, what the "global CAs" are doing is not wholly different in a technical level than what a company with their own internal CA does, except that I hope

Then again, what the "global CAs" are doing is not wholly different in a technical level than what a company with their own internal CA does, except that I hope the global CAs take security very very seriously, and they pass an expensive audit. In the end, it is just some company or organisation that creates a root CA cert and intermediaries, and then jump through hoops to make browsers and OS cert stores add their certs. Not saying it is easy, just that the technical parts are rather similar, the rest being a cumbersome way to prove you are trustworthy by showing off your processes and fences around the signing boxes.