Breaking Bad's finale is widely regarded among the masses for being one of the greatest endings in television history, thanks largely to the death of Walter White. Ending the show with his ultimate demise was a close and satisfying conclusion, curating different threads with a meaningful, if cliché, parallelism that captured the metamorphosis of a shy high school chemistry teacher to a mastermind-turned supervillain who had charmed and terrified fans along the way.
If Walt had lived, these five primary storylines would've completely disintegrated.
Disclaimer: This entire article is based on the writer's opinion. Readers' discretion is advised.
Origin of Heisenberg

Walter White's journey into the world of crime started with one objective: to secure his family's future after a terminal diagnosis of lung cancer. He intended to manufacture meth just long enough to ensure that when he passed away, he would have left a small fortune behind. That initial motivation served as a ticking clock, providing the series with its sense of purpose and urgency.
The poetic balance of the series comes full circle when Walt dies two years later, on his 52nd birthday, as in the very first episode's flash-forward. While it wasn't cancer that killed him, his death still satisfied the prophecy. If Walt had survived, that poetic irony would've been destroyed, and his whole journey would've felt incomplete. The series began with a death sentence; it had to conclude with one.
Accountability for Walt's actions

Throughout five seasons, Walt's behaviour created a horrific trail of victims. He directly or indirectly caused the deaths of Mike Ehrmantraut, Gale Boetticher, Jane Margolis, Hank Schrader, Gomez, and even several imprisoned associates of Mike. His choices had far-reaching consequences, and by the end, he had definitely become a man who was worthy of punishment.
Walt's death was not only a storytelling requirement but also a matter of justice. If he'd lived, prison or exile wouldn't have been nearly so satisfying or cathartic an ending for the viewers. His death was the punishment he could never really evade, however clever or well-planned out his schemes were.
Walt's final confrontations

The series finale, "Felina," is designed as Walt's last stand. Having been on the run for months and having come to the realisation that he's lost everything—his family, his fortune, and his sense of purpose—Walt comes back to Albuquerque with nothing to lose. He pays an old debt to the Schwartzes, kills Lydia, and kills Jack and his neo-Nazi crew in one massive, explosive stroke.
Walt's goal is no longer survival. It's a final, desperate measure to repair what he can and die on his own terms. If he'd survived, the emotional impact and finality of this grand finale would have been lost. His journey concludes not with flight, but with one last act of accountability.
Walt's descent into immorality hit rock bottom
According to Vince Gilligan, the show's writer, Breaking Bad is about transforming "Mr. Chips into Scarface." By the show's last season, Walt had completely changed into a merciless, unredeemable character. Claiming it was "for his family," he had ruined lives, poisoned a child, and deceived his closest allies.
It was too late to turn back now. The impact of Walt's moral fall could be lessened in any version of the story where he survives. Not only did his death make sense, but it was essential. Letting him live would have given the wrong message, and redemption was never really on the table.
Walt's final act of redemption through Jesse

While Walt used Jesse Pinkman throughout most of the show, there was always a tangled relationship between the two. At the end of the series, Walt makes an instant decision that shows he still loves him—he pushes Jesse out of the way of the hail of bullets and gets a fatal shot himself.
This ultimate sacrifice restores a glimmer of humanity to Walt at the very end. Had he lived, that emotional moment would have had little of the impact it did. His last gesture—giving Jesse the opportunity for freedom—was his best shot at redemption.