We don’t need a new castlevania (it’s just a name) when we have Bloodstained that is very much castlevania in all but name (I’ve played both Curse of the Moon and Ritual of the Night when I say this)

I think this is a franchise that aged well. Just like Metroid in a way, maybe it's due to metroidvanias increasing in popularity and appreciation? Same with Megaman, but from the company's perspective these games never sold well so that's why they are probably struggling to support it. Even Metroid barely sold 3 million copies, I feel like it's just the core fans hyping it up and not really buyers to back it up. Another reason is the Banjo Kazooie case, where they can't find any experienced developers that can develop a good Metroidvania. Nintendo found a way for Metroid, hopefully Castlevania and Megaman can too.

Konami didn’t put out the television series, Netflix did. Konami’s involvement seems to be little to nothing more than selling the license to adapt material from the games up to Curse of Darkness sometime before 2007.

Usually, releasing catalogue material and licensing content has more to do with not leaving easy money on the table. Companies have been doing it pretty regularly since the Wii days.

Time for a history lesson guys.

Lets ignore the western stuff. The best selling game is the original but this includes all of its rereleases over the years. At its time it was Symphony of the Night which would revitalize the series the first time (Classic Castlevania had a previous slump). Since then, Castlevania has trended downwards in regards to sales. Non of the GBA games sold as much as SotN, though Aria of Sorrow came close. PS2 games did not sale as much as SotN but the first one sold good. The DS games sold decent, just enough to keep the series active. Later in the PS3/360?Wii era, Koji Igarashi was removed from Castlevania because of his inability to pick the series up. The Wii fighter and Order of Ecclessia bombed very hard. Order of Ecclessia sold less than 10k in Japan. Yikes! Back to the western stuff; Lords of Shadow is the highest selling Castlevania game, but its hard to count it when we know it was retooled to be a Castlevania game. 

Mega Man has a similar history to Castlevania. Mega Man X7, X8 and Command Missions all bombed. ZX and ZX:A both underperformed. Hell, I remember that video of Inafune begging fans to get sales of ZX:A to 100k to continue making more games. Didnt happen and Mega Man went on hiatus as well. Both series have the issue of not being to overtake their highest days. SotN, some of the PS2 games, and the GBA games, The Mega Man X games on PS1, GBA games( Battle Network and Zero); These were the golden age for both series. Both series dropped like a rock after this age. Castlevania and Mega Man died because no cared about the series except the core. 

I blame the fact that both series were locked to handhelds and made very little advancements in regards to game design. While they sold well, they didn't find a new formula to get them through the next generation. They tried with Maverick Hunter X(the cancelled western one) and Lords of Shadow but these have nothing to do with series at all so they failed. 

CAPCOM has already confirmed there is a new Mega Man game in development and they want to take their time with it. It has been rumored for years that KONAMI has been hard at work on a reboot of Castlevania. They know. Its just a matter of time. 

EDIT: Also forgot to point out that it i