I have a couple arguments about that

1 – it’s a commercial interest, they’re in it to make money. remember, this is WarnerBrothers that we’re talking about, not some strapped for cash publication (lookin at you Charlie)
2 – from my understanding and my memory of the way it played out, they strongly indicated and made public statements that the series were still going to keep going with four alternate characters all that were ultimately either going to go away, go their own way in their own series or be revealed to be the real superman. heck, I think it was only two months after his death that they revealed his body had been stolen by parties unknown.
3 – want to see someone they actually planned on killing off? look at what was going on with green lantern at the time, he went crazy, killed ALL his friends and coworkers, took all the power rings except for one and went off to parts unknown as a super powered freak of nature. they had no plans of keeping Hal Jordan around as a likable character and fully expected Kyle Rayner to be the GL going forward. Excellent move, as it elevated the character’s profile and brought on a ton of new readers, myself included.