Industry term related to on-screen credits

In the old days, of movies and television, I believe just the word billing was the catchall used for what you're describing. Maybe it's been replaced, or maybe there are other words for what you're describing that are more specific. Now and then hip words come and go to describe things specific not just to the mass media but everything.

Back when Hill Street Blues was running I remember an actor, I think it was Charles Haid, who got "special" billing after the rest of his fellow players in the opening credits. Something like "...and Charles Haid as Renko". There was even an article in some TV magazine about why this was the case and it was explained as "an industry practice". Maybe Charles Haid was better known or more highly regarded than the other actors on the show. Also, it was a matter of (likely) money.

To go back further, to the Sixties, and the I Spy series it was the other way around. When the show began actor Robert Culp was by far the better known of the two leads as an actor, while Bill Cosby was known mostly as a comedian, and he had a younger following. Still, Culp always got the top spot, right to the end of the series. However, from what I've read Cosby was making vastly more money than Culp by that time. A superstar salary, apparently, rather than a "mere" TV star one, which isn't to say Culp wasn't well paid, just not in the several millions.

But things have changed a lot over the years and I pay little attention to TV trends these days, so I'm out of it. I do think that some of the backstory I'm provided says something about the evolution of billing, "special" billing and the (maybe more) prestigious "final" billing. Then there's type size, or font, as who's names is shown in bigger letters in the opening credits and maybe the closing ones as well. There are so many "handlers" now in show business,and this is a broad category than can include input from everyone from agents to lawyers to (so-called) creative consultants and a lot of other jobs that sound more artistic and even intellectual than they really are.

I'm sorry I can't answer your question as you asked it as it applies to today's TV shows. The best I can add to the aforementioned is that it ain't what it used to be in the "old days" of even twenty years ago; and twenty years from now it shall be different again in totally different ways.

I'm a failure: I honestly don't know if there's a specific term for it.

I usually assume it's the result of negotiations between an agent and producers who've already given top billing to other performers.