Imagine if every single game had to keep reinforcing the history so far. Imagine the sheer size of the intros and dialogues lol
Honestly, they could easily look to comic books for inspiration as to how it's done. Stories across a given writing era are remarkably consistent with each other, and can reference each other with casual aplomb, not in a "hey look how conscious of the universe we are" way, but you can reliably expect Spider-Man to comment on something Captain America is doing much like we comment on local politics -- it's just a facet of our interconnected world.
Castlevania seldom feels that alive, if in fact it ever did to begin with. By comparison, it's more like... a series of plays all with the same framing narrative (but otherwise having little to do with each other) by a sequence of varied authors. Each is aware of and recognizes the prior author's works but the connection isn't fluid; it's wooden and stilted at best. References are made, not because they are a natural organic part of the world the story takes place in, but because it feels like some outside force deigned that the storyteller absolutely
must make a reference or a connection.
The single greatest
moment de vie in Castlevania was the bit where Maria is asking Alucard if he's seen Richter Belmont anywhere and, having not met Richter, he immediately recalls Trevor instead. It didn't feel forced. It was entirely natural and possibly the strongest enforcement of internal continuity by the games themselves in the series. Credit where it's due, Dawn of Sorrow and Portrait of Ruin were also chock full of it (though less well executed), but this was more due to their status as direct sequels. Still, their internal continuity was impressive for a series more typically known for its external continuity.
As an example, consider the difference between hearing a story told by a Korean War vet and the hearing that same story told to you on the Military History channel. The Vet is going to mention Reggie from the 103rd, and how Reggie wrote to his girlfriend every day and how he hated the jello they served at the mess "hall". He'll talk about the fighting and the strategies of course, but in their due time as it's less important to his story. The Military History documentary flips the equation. It's not gonna consider Reggie from the 103rd. It's going to focus on Brigadier Whatshisname and his brilliant use of decoy operations and clever troop movements to outfox the enemy. The priorities are different.
As Castlevania has a very strong external continuity, it comes across more like that Military History documentary. But then you have those moments, with Alucard, Soma, Jonathan, etc., and you get stuff from the guys who were actually there, talking about past events organically like they're actually part of a living breathing world with its own history, like a really well developed comic book does. And then things shift, jarringly, back to the History Channel version of continuity.
And I find myself wishing that we had the more personal and interconnected living history side of Castlevania all the time.
That's why I hope the Netflix series continues past Trevor and covers AT LEAST Simon, Leon, and Richter as well. In most fandom circles, they are often considered "the most important" Belmonts, and the Netflix show has the potential to nail the living history angle that the games have usually flubbed on.