I just don't see a trusted and admired leader ever doing that to his people and world at large so it's hard for me to answer that even in a hypothetical sense. But even when I consider it as a maybe scenario I just can't see everyone supporting a dream they can't wake up from.
And what's your opinion on just how the new dream world be? A shared thing like I mentioned? Split into individual? Madara-centric or personalized for each one?
Would you want to be in a world where the definition of perfect happiness is decided by someone you hate and diametrically oppose?