Theoretically speaking, if top holders continue to keep their millions, all Nxt idea became cosidered "scam" and stop working. So top holders are interested to distribute most of their stake from the beginning.
But it is only theory. Will it go to practice - we'll see.
I can only speak for myself.. but I started with ~4.9M Nxt.. so far I've sold and given away a total of 500k or so. When the price was still low I gave 2000 Nxt to about 20 people. As the number of users have grown, so has the price... distributing your Nxt is indeed a very good thing.. and it's necessary for Nxt to succeed. It's impossible for it to compete with other coins otherwise.