I will begin by saying that this theory came to my head as a crazy thought, like when you open the fridge and have a idea, so please take it with a grain of salt since it can be a bit overdramatic and completely off the mark. Also it contains heavy spoilers for the game, but I think if you are reading this you already beat it, right?
The message is hidden on the plot itself. Like, what if IGA
knew or felt like he wouldn't have a chance to work in another major Castlevania title? What if he put these feelings in this game? Thats what I will try to show now.
For starters as markers:
Shanoa is IGA
Barlowe is Konami
Albus is (lets call they person "X")
Dracula/Castlevania is ? (franchise?)
IGA wants to give all of himself to make games he love (Shanoa wants to accomplish her mission) but exhausts itself more and more with low-budget and possibly few time to make them, losing hope that he would be given the chance for his full potential by Konami (Shanoa loses her memories and emotions because of Dominus).
While someone at Konami or outside (person X) is trying to get hold of the Castlevania franchise production (that may not had happened at the time, but could be a inherent fear, maybe is related to metroidvania genre booming?) for some kind of reason, like Albus tried to take Shanoa's place as Dominus' host.
First we are made to believe that its Albus fault that Shanoa lost his emotions and memories, but it was truly Barlowe's fault (aka Konami, that made IGA work with low budget and maybe work in harsh conditions).
Then even after discovering that and trying to stop Barlowe while he spouts the famous lines "How dare you, you even forgetting, who raised you. You... Stupid disciple" (as Konami helped IGA rise) she fails to stop the calamity and Castlevania rises again (like "even without you, there still will be Castlevania games").
As we all know Dracula is defeated yet again by using his own powers against him (maybe IGA was already planning to make a solo project, even if his high loyalty wouldn't let him part ways with Konami at the time, after all he is a very humble man, maybe that can even correlate with Konami's fear of a 1999 game) but with the cost of a friend, that only asked to see she smiling one last time, while she lost everything.
Maybe person "X" are the fans. Konami kept saying that there isn't interest enough in this type of game anymore, while fans kept fighting to maintain the franchise alive and IGA's willpower burning (correlates with Barlowe/Albus antagonism). By leaving Konami, maybe IGA thought it would mean let his old fans behind since maybe in his head that would mean that he wouldn't be able to make CV-like games anymore or that Konami would continue making CV games even if different, that would keep the old fans there far from him.
I thought it was funny that the last game made by him that happens in the timeline, is the one that seems to have a rushed ending as if incomplete (like the franchise without the 199 game) and tells about losing everything.
So what are your thought? I know it may sound absurd, it kinda sounds to me too, but not like something that is impossible. Well, I wanted to return with some kind of lets say... more "normal" thread, but it seems it wasn't this time haha