And moreover partnering with Sony WOULD NOT HAVE SAVED THEM as they had burned their customers over and over AND OVER for the better part of 5 years. Nobody was gonna buy Sega hardware even if they came out with the baddest console in the history of the universe!
The reason Sega died was threefold, 1.- They royally fucked their retail partners on the Saturn by doing a "sneak launch" that left several 800 pound gorillas like Walmart out in the cold. this pissed off those retailers so badly that many of them swore to never carry another piece of Sega hardware, this crippled their retail channel overnight and it never recovered.
2.-The thing that put the first nails in the coffin though was the fact that SOA and SOJ weren't even on speaking terms, with things getting so bad that SOJ would even make announcements that would hamstring SOA! From what I read SOJ was a bunch of elitist pricks with a serious case of NIH so they treated SOA like a red headed stepchild and kept them out of the loop on what they had in the pipe.Depending on how you view 3 this can be seen as justified, though it still crippled the company.
3.- But what ultimately destroyed their sales was the fact that SOA simply refused to let go off the Genesis and launched one failed add-on after another, all of which left the consumer feeling like they got scammed as they spent hundreds of dollars (nearly $700 if they bought a Genesis, Sega-CD, and 32x at launch) and all they got was piss poor support, lousy titles, and in the case of the 32x a device that was dying less than 90 days after launch!
Many blame the fact that the Saturn was really designed to be a 2D gaming monster that had badly supported 3D just bolted on at the last minute but I would argue that by that time they were already dying. I was a HARDCORE Sega fan at the time but after getting burnt on the Sega-CD (I picked up a 32x when they hit $25 with 3 games but we all knew it was a dead system by then) I was just fucking done with the company,after seeing the incredible promise of Sega-CD just thrown away (anybody who says it couldn't be a great system really should play Lunar) I honestly didn't trust the company not to abandon their hardware before enough decent games came out to justify the expense. I avoided the Saturn altogether for the PlayStation, grabbed a Dreamcast when it hit $75 (and the pirates had already cracked it, makes a great NES/Genesis emulator box) and then went PC and never looked back.
At the time I was big into IRC and all I heard from the Sega channels was the same story, guys that got burnt on Sega-CD/32X that refused to give the company another shot, a few picked up Saturn only to see SOA refuse to import the best titles thanks to their pissing contest with SOJ, instead sticking with frankly shitty western games (most guys forget that before the big 3D shooter and RPG craze on PC that western game developers were REALLY piss poor compared to their eastern counterparts. Bad controls, lousy levels, and lame graphics were standard for western made games by and large) and leaving the best titles for the system overseas. By the time the Dreamcast came around? Even the most hardcore fanboys just had had enough, they had a shitload of hardware with little to no decent games and felt ripped off. You have to remember they hyped the shit out of Sega-CD/32X so a LOT of guys (myself included) got taken and when you sank nearly $500 and could count the good games on 2 hands with fingers left over? That is NOT a good sign!
So no Sony could not have saved them, they were already dying by that point. They should have never released the CD/32X or at least committed to giving them 3 years of game support, even if it meant dropping the royalties to nothing just to get devs on board,if they would have done that along with a promise of 3 years on Saturn? Then they might have made it, at least built enough good will to get their fanbase to get on board with Dreamcast which really was a kick ass piece of hardware, but shitty management, too many pieces of worthless hardware, and too much infighting had them dead by 2K and nothing would have saved them at that point.