It's huge. Depends what kind of LLLL.net you are talking about...There have been some very big sale's of CVCV.net, VCVC.net, and quad premium LLLL.net. I will send you a PM of something you should def. check out if you are interested in LLLL.net
I think there will be some value of them after a year or two. You can invest in them. Some premiums are already selling for good prices
People are diversifying into other major extensions of LLLL domains. You might not get a huge amount for your .net's but if you choose the ones that you go after carefully, there are some very good ones to be had out there in the aftermarket and from dropcatching. We ourselves are enjoying considerable success picking up some prime quad premium pronounceable .net domains in this category. The other option on acquiring these is quickly flipping them for an immediate profit in bulk. They'll always be tens of thousands of domains dropping every day and the market has more than enough room for lots of beautiful domains across many key extensions. If you are inexperienced, do not go for absurd extensions though, like .asia, if you do so, you'll find it much more difficult to get your money back. Stay with the leading extensions only. .Com is your best of course, .co.uk and .de follow closely behind, although for the latter it would help if you spoke German. Take a look at some of the others by all means too, but do your research first.