After watching the last episode I imagine the pitch session going like this.
"So, it's going to basically be Dance with Wolves but with Boba Fett and Sand People."
"But that's not enough for seven episodes."
"Okay, how about we detail the back story of Ming Na's character? She's popular with the fans, right?
"And???"
"We add the Mandalorian? But not just as a cameo, we do an entire episode about him and include some plot centric stuff that you'll need to watch in order to understand Season 3 of the Mandalorian?"
"Okay... and???"
"I guess we could do an entire episode about Luke and Grogu training because the fan boys were very vocal that they did not get enough Jedi training as part of Rey's character arc. Potentially we could even through in Asoka, because she's a fan favorite, even though she doesn't think Grogu should be trained. But I don't really see how we could that in a series about Boba Fett."
"Yeah, we don't see that as a problem, but the story still doesn't have enough zazz. Could you throw in some superfluous characters from the extended universe? They don't have to figure into the plot in any way, but it will make the fans happy."
"What about... what about Black Krrsantan?"
"Fine, whatever, but drop the word black, it sounds racist. Also try to work in the Galactic Star Cruiser, that's going to be wicked! Also, make one of the characters say 'wicked,' for no good reason in a jarring manor where it doesn't fit the story."
And that's how the Book of Boba Fett was written.
It's shows like this that makes me wish HBO had bought Star Wars and not Disney.