Doesn't making Trek entirely an "alternate timeline" thing kind of detract from the point of the show which was to show humanity's potential? If it isn't OUR future, that kind of makes the whole thing feel a bit hollow.
Except any viewer who is actually sane and understands the difference between fiction and reality would already know that it's not our real future. It's a bloomin' TV show with actors on sets in front of cameras. Everyone knows that. So obviously it's not meant to be a literal proposal for what the future could be. It's an aspirational symbol, a representation of what a better future could look like, a model for the kind of future we can potentially build. It's not about "This event will happen on this date in exactly this way" -- it's about "This is the way human beings could live and treat each other in a better world, if we work hard enough to make such a world."