Yes we know you want the Comeback & Enlightened because you’re always talking about them. They weren’t that great & the6 didn’t end too soon.
As for Rome, it was supplanted by GoT. Rome was very expensive, lasted 2 seasons but didn’t get great ratings. It was poorly advertised, showing blood & Julius Caesar’s red painted face all the time. If they’d used other imagery, maybe people wouldve bothered watching, but it looked like a 1950s biblical/Roman/Egypt saga from the 1950s in the previews. Lots of yelling, painted faces, swords raised, puddles of blood. Really poor marketing.
So Rome was cancelled due to poor viewership and HBO was greed to pick up Game of Thrones, which opened up with magic zombies. The very first scene is about guys from a scary icy castle hunting for people & coming up against magic zombies who commit an atrocity in a snowy forest. It was practically an instant hit.
The main character was unexpectedly killed off. This was super-surprising to younger audiences who never saw Psycho. How can they doooooo that? And GoT had a blonde sexpot taking off her clothes in practically every scene she was in...plus she had witchy superpowers. And then...dragons.
Compare that to the underwhelming sexiness of Cleopatra in Rome and her dwarfy companion (who was no Tyrion Lannister). Cleo was dull as dishwater.
Atia of the Julii was sexy, but too campy by a mile. She was no match for Cersei Lannister.
Servilia, let’s face it, had seen her best years a few decades previously.
Octavia was wan, skinny & gawky looking when they forced her gross sex scenes upon us.
Octavian was clinically brutal, while Joffrey was maniacally brutal.
Cersei and her brother Jamie weren’t as horrifying in their incest as Octavia & Octavian in Rome.
Julius Caesar had a bit of a speech impediment and couldn’t hold a torch to Tywin Lannister. He was better in a secondary role as the leader of the wildlings.
Basically, GoT took the characters from Rome and improved on them while adding magic/witches/dragons. Rome was a dress rehearsal for GoT. Unfortunately GoT had a Wizard of Oz-type ending where everybody goes through hell only to learn that it was all going to be neatly tied up in a bundle after all kinds of people (and dogs - large & small) went through a shitload of suffering for you.