Warning: SPOILERS for Star Trek: Picard Season 3 Finale – "The Last Generation"Star Trek: Picard season 3 showrunner Terry Matalas explains the decision to turn the USS Titan-A into the new USS Enterprise-G at the end of the series. The Titan was Picard season 3's hero ship, which endured battles with Captain Vadic's (Amanda Plummer) heavily-armed starship, the Shrike, a Changeling and Borg takeover, and the Titan even took on the Borg-assimilated Starfleet solo. Surprisingly, the Titan was rechristened into the USS Enterprise-G under the command of Captain Seven of Nine (Jeri Ryan) one year after the Titan and the USS Enterprise-D saved the Earth from the Borg/Changeling alliance.
Terry Matalas was asked during a Reddit AMA about why the Titan was turned into the Enterprise at the end of Star Trek: Picard season 3. The move merged the legacies of the two legendary starships, as opposed to keeping them separate. Read Matalas' response and quote below:
Terry Matalas: In our mind, we were writing the origin story of the next Enterprise and that the Titan name would live on in a proper new Luna Class ship. The Titan-B. Hopefully glimpsed in some future show.