Money isn't everything. ArenMook wants to make games, not UI - NGUI was made as a needed component for a game he was working on and it has just grown to be so big that it demands attention. Offloading this to Unity to obsolete it seemd like a good idea at the time, to be able to spend his time better. We all only have limited time, so once needs are met, we should be able to choose what to do with it.
Since then NGUI has developed further and in a different direction than what uGUI has, so they have changed from a predeccessor->successor relationship, to two competitors instead. Your suspicions are based on ourdated data - that "Intersting Times" post is from 2012.
The simple argument for buying NGUI is that it's available right now, where uGUI is "at some point in the near-future". If that doesn't convince you, then you need to look at features, which seems to have a big overlap, but it's not really clear exactly how they overlap, since all we have to go on is two youtube videos, one being ArenMooks talk from a while ago and the other being the new preview.
ok cool. so can you convince me why, i (and others of course) should buy Ngui when you helped to make the New free Unity GUI better than NGUI?
and i still dont get why you did that, it just makes no sense? you have the best selling asset on the asset store, so why would you help to kill it? you're obviously very clever, and thats just down right dumb. sorry to be harsh but it is. surely the obvious thing to do would be to make sure ngui is so good it wipes the floor with the new free version, but you did the exact opposite and made the free version better than your own paid for version??? you said you explained this previously but i cant find that, can you post a link where i can read your explanation for that?