One great thing about PoW is that it allows for a fair and controlled distribution. Any ICO allows for shill accounts to distort distribution and than there is the added problem of the last minute change in NxT's ICO(Like was done with maidsafe coin) compounding the problem.
This is an issue, but shill accounts can be kept to an acceptable limit through the requirement of purchasing an initial stake rather than giving the ICO stakes away for free. NEM took the latter road and it's clear by now how things have turned out for those idiots. Their own leader, the now-forgotten UtopianFuture, accidentally signed a post from one of his own shill accounts by his UtopianFuture name, mistakenly thinking he was signed into his main account, and went down in utter disgrace. But since NXT stakes had to be purchased with bitcoin one could not simply multiply their stakes limited only by how many new accounts they could manage to create. Anyone who wanted multiple NXT stakes would have had to pay real money for them and I doubt many would have wanted to risk more than 1 BTC on something most people saw as a simple scam at time of ICO. This is why I think the number of original stake-holders is much higher than the low-ball estimates NXT's critics are always repeating, which range from 2-10. Anyway there's no way to know the exact number. Was the ICO perfect? No. Is it a critical flaw in the NXT ecosystem? I don't think so. If NXT has a lot of valuable features to offer the crypto world I'd say those features outway any unfairness in ICO. I'm not that bothered if a few lucky or smart folks get rich off of unfair ICO, if NXT allows me to use a decentralized marketplace, currency exchange, voting system etc. I'll use it just because it's useful to me. If enough other people see it that way NXT will take off big!
I agree that it was unlikely that the shill accounts came from investors. If I created an alt with a couple partners I would have taken some of my own BTC and invested it across many shill accounts to make it appear that the distribution is greater than appeared. It is impossible to know an exact number. Minimum would be around 5 controlling over 50% stake and max 73. Our estimates of 5-9 is a very rough guess judging from initial blockchain distribution graphs (which were subsequently removed because they were far too granular.
https://nxtblocks.info/#section/blockexplorer_distribution shows a rougher approximation with the highest category being between 1 million and a billion where a previous breakdown reflecting only a handfull accounts between the 10 million and billion. This data wasn't coming from Nxt "haters" but the NxT blockchain itself. Of course Nxt proponents will always claim that most of the initial coins have been sold off to new investors and distribution is much better now. The problem with this thinking is that there doesn't exist any evidence to support this and some good evidence to show that there hasn't been a rush of new investors into the Nxt Ecosystem.
You want some evidence. Look at the Nxt Forum.... keep in mind that someone investing in Nxt is far more likely to participate in Nxt forum than bitcoin because it is an obscure and niche alt where you really have to be involved to own some.
https://nxtforum.org/Most Online Today:
134. Most Online Ever:
509 (August 15, 2014, 01:19:36 pm)
This includes shill accounts as well reflecting a very small community.