After touching all-bought-out status a couple times in the last month, a week of heavy drops has left us with 48 NNNNN.com domains available to register as of this morning.
That is still very few, as 100,000 of these domains exist in total.
It is quite possible that in a year's time or less, these domains will be 100% registered and all drops will be picked up, similar to what exists with LLLL.com domains. Unlike with the previous buyout of NNNNN.com's where 20,000 domains were bought in a frenzy in a couple weeks, this one has been years in the making, with a steady registration pace of around 13/day. Therefore it makes sense that the buyout doesn't "stick" immediately, because it is not a buyout like the last one.
The buyers nowadays are not looking to cash in on the next domain buyout bubble like LLLL.com's in early 2008, when bad letters were going for $50-$60 a pop. We all know how that ended, both LLLL.com's and NNNNN.com's crashed, LLLL.com's back to being around $10-$15 for bad letters and NNNNN.com's back to reg fee.
Long term, the fundamentals for NNNNN.com's are likely as good or even better than LLLL.com's, and the sneaking steady registration is a sign of that. A significant portion of these domains are actually used by end-users for traffic, redirect, or real developed sites (mainly Chinese but other foreign and English-language sites as well). Plus, whereas there are 450,000+ LLLL.com's, there are only 100,000 NNNNN.com's, and a random NNNNN.com is likely to get significantly more google hits (and therefore possible uses) than a random LLLL.com.