Compare the top accounts with top miners, you will find most of the top accounts are not holding coins sleeping, but they are mining for profit to get more coins.
Don't forget that they are also mining to secure the network. The number of transactions is still very low, so for somebody already having millions of Nxt the profit from mining is insignificant relative to his holdings.
They should giveaway some coins to the new comers, for example, if each of them take 10,000,000 Nxt for giveaway to 10000 users with each one 1000 coins.
This should cause the value of Nxt to plummet. Why buy something that can be obtained for free? And 1000 coins is too small of an amount to be useful for mining, so how exactly will that help those 10000 users? Most likely they will just forget about it after the novelty wears out. On the other hand, if they paid $10 for those 1000 Nxt (the current market value), they are more likely to get involved and use it.
If the top stakeholders are not selling, this is because they find the current price too low. It is a free market after all. If one is serious about investing in Nxt, one has to buy it.