A supply in the billions was once controversial until it was popularized by Doge, NXT and Ripple. Now many coins come out with a supply in the billions. It could very well be the case that a supply in the trillions will work better but we don't know as nobody has taken the initiative to try it.
I think from an international perspective the international monetary supply is around $20 trillion and then derivative, assets and other things do add up to $500 trillion to $1 quadrillion. So having a NEM supply at 800 - 888 trillion does fit that global scale.
I think it would also work better for tipping. Doge used to get a lot of interest as people were tipping each other millions of coins but nobody does this anymore because 1 million Doge = $200+ and you aren't going to tip a stranger $200 bucks+. People don't get as excited over a free 10,000 coins anymore. This change would mean each stake would get around 250 billion NEM each and that is a lot of tipping millions. It is a psychological thing but many people like the sound of millions and billions.
I don't think the motivation from anybody here is to cause a riot or a meltdown. I think we have to remember we are still in the innovation phase. The user base of this digital currency technology is only 500K-2M people when the internet in 1989 had up to 3 million. We should always be trying to take every unprecedented initiative we can with the hopes of introducing this technology to more people. One form of that, I guess, could be "much NEM much wow" where new users are lured in by receiving millions of coins.