You know, it is quite strange that this question hasn't been posed more often, considering it was the sole driving factor of everything that White rose did, and the underlying invisible hand that guided most of the "protagonists" actions as well.
I suppose it technically doesn't matter if the machine was real, (i.e., if it "actually" worked or not) since it still acted as the chief motivating factor in White roses universe. Like most things in Mr. Robot, I think it was more about what the machine represented than what it physically did.
If I were to guess the directors intention, I suppose the machines role was to underline the shows competing visions of what it truly means to create a new world, or whether that's even truly possible.
One vision(White rose's) required sacrificing the present world completely, throwing away all of the bad, but also, all of the good- including the memories and personalities people had cultivated for their entire existence- and exchanging it for a parallel universe were things (possibly) could be better. That's a huge gamble, and only one that a truly desperate, cynical person would make. Even worse, White Rose could have even believed it possible to just continuously jump from one parallel universe to another, effectively searching until White rose found the perfect world, or one that had the most equality, freedom and equity. The madness of not accepting reality, and actively attempting to usurp it instead of putting in any effort to positively change it (and with all her resources, she surely could have), is clear here, and its almost painful to think about how much someone would have to be hurting for them to spend so much time creating a machine for the singular purpose of no longer existing in their current reality.
The other vision (Elliots) was sort of always lingering in the back of his mind- and that is that we must embrace the good of our universe and fight to change the things that we see as unjust. For instance, the massive redistribution of wealth that occurred in the final season was an act of vengeance, sure, but it was also the ultimate way of altering the present reality just enough so that the entire present could be redeemed, and the world could move forward in a way that could truly start to amend all of the bad that came before it. I think its a much more sober vision, as everyone knows you cannot, no matter how much money and power you have, bring back the dead.
Both of these visions of "change" are completely tied to both Elliot and white rose's mental and emotional states. Elliot, who had been fighting himself the entire show, had both oblivion and destruction, and creation and resurrection in his heart and mind during everything he did. He escaped through compartmentalizing his pain, creating alternate personas that he could tap into whenever they were required, but during all of that, he still did everything he could to commit to changing the very world he lived in, and retained a moral compass that only strayed away from his will a few times throughout the entire show.
Whiterose mistook Elliots destructive rage to be in the same class as her own, but she did not realize that Elliot would never give up on the world like she had.
Suffering from the severe trauma of Gender and Body Dysphoria, and living with a mind so corrupted by the trauma of loss, self-rejection and alienation from society, she saw no redeeming qualities in the world and did not see the point in attempting to change it, but simply wanted to wholesale abandon it, no matter the cost. White Rose's complete rejection of her own pain led to her attempt to usurp reality in order to avoid the sad truth that she needed to eventually accept herself, her trauma, and her loss.
OF course, while I watched the show I felt differently about White Rose, as I suspect many people did during their initial viewing.
while watching originally, I too was immediately enamored with the possibility of White Rose's machine, and felt like it was simply cynicism on the part of those who did not believe in White Roses machine- after all, Why wouldn't you want to believe that it would be possible to make a world were everyone could be happy? But, the more I thought about it the more I realized why Price and her colleagues thought she was out of her mind- the sad reality of it is that Utopias don't exist- not even in our fantasies.
Even if it was possible, what kind of desperation would you need to feel to destroy everything we have ever known, for only the possibility that we may find a better world on the other side of it?
Putting that much trust into such a massively desperate person, who had no qualms with killing hundreds of thousands of people, even if they truly did think it was "reversible", is a madness far beyond Elliots.
That does leave one question, however- What could have been shown to Angela to make her such an ardent believer in the plan? And what of White Roses actual inner circle? What made them so confident in White Rose that they would sacrifice everything for her vision? I don't think Angela could have been so easily swayed with words. If she was duped, It boggles my mind as to how. She wasn't exactly the most naive person, and easily manipulated and saw through others, much like her father Price.
ANYWAYYYYYY, While I wish we were told more about the machine (and especially whether White roses' plans could actually come to fruition) I think leaving it as an opaque message on the nature existence, trauma, exclusion and despair was the more powerful move.
An ending like that, while it may cause the more cynical critics in us to roll our eyes, is powerful because we are allowed to interpret its meaning. We are allowed to believe or disbelieve White rose, and that is sort of the Rorschach test that makes a work of art like this one truly stand out. How much do we want to believe? How much do we need to?