While successful in Japan, i believe the Sega Saturn is viewed as a forgettable product that's not a priority to replicate for SEGA, besides that, the current company is not the same one as it was back then.
Most of Saturn software has already appeared elsewhere.
Guardian Heroes, Radiant Silvergun. Most shmups, fighters etc are available elsewhere. A big reason to own Saturn were the fighters and shmups, those are bested long ago.
Sega's own games like Virtual On, VF, VC, Sega Rally, Daytona, Panzer Dragoon and Nights they're all playable on other systems as well and often superior. Some of them aren't, like PD Saga, Dragon Force, Shining Force 3 trilogy and Holy Ark. But I would say these probably aren't worth it for Sega to overhaul.
Well, that's irrelevant for the collector's market. And it's also irrelevant because ports released elsewhere don't dismiss their existence on the original hardware. Otherwise, i can dismiss everything, because i have a desktop machine that can emulate everything (including the Sega Saturn) and there's barely anything exclusive on home consoles apart from the Switch alone, haha.
Anyway, apart from the fundamental irrelevancy of ports existing elsewhere, it's also not true in this particular case (funnily enough, it is true in most cases for most home consoles,
except the Sega Saturn). A significant portion of Saturn's software is exclusive on the machine, and exclusive to Japan. Thanks to efforts by its dedicated community (especially recently in 2020/2021) we have access to them via quality translation patches, but there are many more exceptional video games stuck there because of the language barrier: Princess Crown, Wachenroder, Terra Phantastica, Tengai Makyou: The 4th Apocalypse, etc.
Another portion consists of close-to-perfect or perfect-arcade-ports, yes. But what separates these from the arcade originals (only available nowadays via MAME/Other emulators or some of the collection re-releases), apart from their physical availability/collectability, is that most have varying degrees of polish or extra content exclusive to the Saturn. In some cases a lot of extra content that by comparison loading up MAME or whatever official collection of what is essentially arcade roms to play the bare-bones arcade version is like playing a demo of the thing. Like say, Street Fighter Zero 3 (Alpha 3). I can emulate that on anything or play it officially on a slew of collections, but that's just the arcade port. The home console release (Saturn/PSX) had a ton of single-player content and between the Saturn version and the PSX version the Saturn version is better with all the single-player content of the Playstation port and extra modifications/polish exclusive to the Saturn.
And lastly, another portion consists of games that are shared with other machines, but some of them are best played on the Saturn. Like Policenauts (which recently got a fantastic fan translation) Twinkle Star Sprites (with a huge amount of content exclusive for the Saturn), Vandal Hearts - Ushinawareta Kodai Bunmei (which is a better version than the PSX one and the translation patch goes way beyond with a whole slew of improvements you can
read about here), etc.
Guardian Heroes and Radiant Silvergun are emulated digitally available ports only available on Xbox products, yes. They're nice alternatives if you have an Xbox product (i don't) and don't have a Sega Saturn. But that's what they are - alternatives. If you have a Sega Saturn, then you're acquiring and playing Guardian Heroes and Radiant Silvergun, because they're the physical real deal perfectly intended to be on the original machine, you can buy them, collect them and re-sell them later because they're never losing their value as a collector's item. Nights into Dreams has a fantastic remake, i agree, though it does control better with the Saturn 3D Pad and there's some content missing, also Christmas NiGHTS - which is an unlockable in the HD version - is basically a shell that's missing all of the content that made it great. With that said, it's a perfectly viable alternative. But it's also fantastic on the Saturn, it's an iconic game and a no-brainer to collect.
The Panzer Dragoon Remake .. is less of a 'fantastic' remake, and more of an attempt i highly respect but fell a little short of its intended mark. The artstyle of the remake is far less cohesive than the original. The camera system, the controls and the hitboxes range from being slightly worse than the original to irritatingly bad, they're inconsistent. It's a decent remake, and even if it was a perfect remake, that doesn't superseed the original; same way the RE Remake doesn't superseed the original.
