Space Channel 5 :(

Pretty much any series of sports/racing games that is named after a real figure besides John Madden and maybe Tony Hawk.

• Bill Walsh (Electronic Arts)
• Brett Hull (Accolade)
• Charles Barkley (Accolade)
• Colin McRae Rally (Codemasters)
• Ken Griffey Jr (Nintendo)
• Kobe Bryant (Nintendo)
• Michael Jordan (Electronic Arts)
• Mike Tyson (Nintendo/Codemasters)
• Satoru Nakajima (Varie)
• Shaun White (Ubisoft)
• Tiger Woods (Electronic Arts)
• Wayne Gretzky (Various)

You might say that some of these series don't really count, because they were effectively continued under different names. And you'd be right. But I do find it interesting that the genre's history is littered with critically and/or commercially successful brands that are doomed to lie dormant.

Some from the PC perspective:

The Big 3 in western RPGs all won't have any sequels anytime soon.

• Wizardry did get a remake/remaster (it's a visual 3D skin pulled over the original 1980 code, which is still fully intact under the hood), but the last mainline game, Wizardry 8, came out in 2003 and even then, the studio and publisher Sir-Tech had to rent out ad space in north America just to get the game out the door. Even the Japanese spinoffs (which are based on Wizardry I through V, but not the newer titles) have pretty much died out by now.
• Might & Magic had one game, Might & Magic X: Legacy during it's entire lifetime as an Ubisoft franchise, and they dropped support 3 months after release with several bugs unfixed. It's Heroes of Might & Magic Spinoff seems to still be doing okay, but is also still far from it's former heights.
• Ultima hasn't gotten any sequels to Ultima IX, though to be fair Ultima Online is still going strong after almost 30 years even though the last update came out over 10 years ago.

The great Wargames from the 90's, Battle Isle and Panzer General and their spinoffs (History Line, Incubation, People's General, Fantasy General, Star General), didn't get any new releases in over 2 decades. Panzer Corps and Panzer tactics are pretty blatant copies of Panzer General II, but the original hasn't gotten any sequels in almost 30 years.

Unreal and it's spinoff, Unreal Tournament, didn't get any new releases in decades as Fortnite has pretty much replaced them in in the heads of the higher-ups.

Oh, and since Valve can't count to 3, all their franchises won't get any successors.

Richard Garriott is trying to  regain the rights to Ultima after EA got sold to Prince Bonesaw, using a loophole in US copyright law. Unfortunately, Garriott's work since he left Origin hasn't been great - a MMO that didn't even last a year, a Kickstarter F2P game, and dabbling in NFT stuff. So I guess we'll see. Hopefully he'll partner up with a solid RPG house to revive the series. Apparently, Robert Garriott and Dallas Snell were tasked with trying to keep Richard's ideas grounded in reality. 

Xenosaga, unless you count Gears/Saga/Blade as a single franchise.

Dragon Age, definitely. And, hate to be that guy, but Mass Effect as well. I just don't see EA putting up with Bioware for long enough to make another entry, and by the time they inevitably get shut down the franchise will have been out of pop culture relevance for too long.

Series that depended on now outdated tech. Duck Hunt, Eye Toy, Kinekt Adventures...

I wouldn’t say never for Xenosaga… it seems to me at least that somebody’s cooking something up for that franchise.

EarthBound/Mother: I'm referring to a very new game. A remaster, remake, or reimagining remake of any of the games is possible. I don't see a Mother 4.
Chibi-Robo
Project Gotham Racing
Burnout
Chrono
Leisure Suit Larry
Duke Nukem

Earthworm Jim.