Even when the books came out, the end was "choose the outcome you want"
First of all, the various books about the end of the World of Darkness were always optional. They never forced anyone to play the metaplot. And they all contained multiple possible ends, at times based on what the players did.
For Mage, the book would be Ascension.1 It contains a call out to "Choose what is the outcome" in the starter, with emphasis added:
The Aftermath
What comes after the end? That’s for you to decide. White Wolf is
ceasing publication of the current Mage game and its World of Darkness cousins. Something will rise from the ashes, but it won’t be the same.
You might decide that you still want to keep telling
stories in this world, the one you’ve spent years in. Go
right ahead. Nobody’s stopping you. You can decide for
yourself what shape the world takes after Ascension. You
can use years of past sourcebooks from all the World of
Darkness games to build an elaborate chronicle inhabited
by scheming vampires, brutal werewolves and of course,
ingenious mages. Using foreknowledge from this book,
you can take all of them to the brink of Ascension, and
then send them off in a wholly new direction, in an altered — or hauntingly unchanged — World of Darkness.2
The book itself describes itself as a suggestion in all chapters, and makes that very clear in the "How to use this Book" area (emphasis mine):
Chapter One: Signs of the Times suggests a timeline
for building up to the Grand Finale itself. You decide
whether the end is Armageddon or Ascension. [...]
Chapter Two: Judgment is as close as we get to
providing an “official” story with which to introduce
Ascension. It delves deep into years of metaplot to
hatch ancient schemes that finally come to fruition
now, in the lives of your characters. [...]
Chapter Three: The Revolution Will Be Televised gives us a different version of the end, this one
determined solely by the Technocracy. [...]
Chapter Four: The Earth Will Shake shows us
what happens when the universe itself fights back,
by throwing the biggest, raw physical fact imaginable
in the faces of all willworkers — a meteor hurtling at
Earth, not just in physical reality but also in the Umbra.[...]
Chapter Five: A Whimper, Not a Bang demonstrates what happens when the end of the world takes
place off-stage, removed from the eyes of Sleepers and
many mages. [...]
Chapter Six: Hell on Earth is the worst possible
ending — it’s not Ascension at all, but Descent. [...]
Chapter Seven: Designing Ascension tells you
what to do if you don’t like any of the preceding stories,
or perhaps you like elements from each but want to
brew your own concoction from them. Tips and techniques for building your own version of Ascension (or
Armageddon) are provided, including some hints on
what Storyteller characters to use and what metaplot
to resurrect.3
Each of the chapters is written as either a possible way or with a huge What If... before the premise for this chapter.
The 20th-anniversary edition of the 2010s explicitly has put in multiple boxes about many of the larger metaplot-altering events that, all together, pretty much boil down to "We don't tell you what of this has happened, or if it happened at all. If you don't like it, ignore this box. Otherwise, here's a summary. It is up to you to figure out what happened, and how to incorporate it into your game. We set this revival's baseline to before the End Times, everything else is up to you."
Conclusion
If you don't like Ascension or Time of Judgement, just don't run an End-Time plot. Then it just doesn't happen. If you want to incorporate some sort of end time, let me leave you with some words from the last Final Words Mage ever had, pointing out why such a plot might be interesting:
Why is Ascension desirable? What makes it so precious
that mages would suffer, kill and die for it?
[...]
[W]e muddle along, approaching our finite time on
Earth with varying degrees of passion, fear, apprehension,
generosity and small-mindedness. We are all tapestries
composed of doubt and desire, selfishness and a higher
drive. Each of us is the story of the world we know.
Yet at the same, time, all of these instincts, thoughts,
emotions and relationships are contained within us.
There is no escape; we have to resolve these paradoxes.
When pain contradicts our desire for comfort, we search
for surcease. When ignorance contradicts our need to
know, we learn. That’s no different than what mages
strive for. The paradoxes are different, but the motivation is the same. After each moment, their stories, like
ours, move forward.
Mage is a game about these stories. Mages craft grand
tales, taking the universe and weaving it on the looms
of their paradigms. Ascension is not the end, it is the
whole meaning of that story. Mages encounter Paradox
when the bedrock of their beliefs clash with the rest of
the universe. It’s a continuity problem, a strange leap
that makes the story seem less authentic. It calls the
meaning of the mage’s life into question.4
1 - Ascension - Time of Judgement, Stone Mountain (2004).
2 - Ascension - Time of Judgement, Stone Mountain (2004), p.16-17.
3 - Ascension - Time of Judgement, Stone Mountain (2004), p.17-18.
4 - Ascension - Time of Judgement, Stone Mountain (2004), p.219.