Solution to what? Being anonymous?
Well, it depends. Either that or for keeping things private which is what Alliance or WASTE are good for. You aren't really anonymous when using waste. It's more like a virtual private network where data can be transferred in a secure (encrypted) way, but someone outside knows whom you are connected with and can possibly analyze the (encrypted) data you transfer. So the attacker is for example able to guess what you are transferring by looking at how much traffic you generate. Also you are not really anonymous to others inside the network, because you connect to them. If you create an open network that everyone can join you loose all benefits.
Isn't usenet pretty much perfect for the use? I mean you have a huge number decentralized servers everywhere,
Yes, but it depends on a lot of factors. First of all the admin of a server can always watch you and since data isn't encrypted (unless you encrypt postings) people watching know what you are downloading. Of course it's hard to have an eye on all servers, but your ISP knows everything and the server operator too. Also messages you write can usually be used to identify you if you don't taker lots of precautions. You can operate your own server of course, but this partly takes away the benefits of Usenet, especially when you make a private one. Also it can be costly if you have to store and transfer all the data.
usenet was the internet before HTML.
I have been using Usenet for a long time and I don't know why people always say things like that. Historically you didn't even need to have an actual internet connection to access them. HTML is a markup language. I guess you mean HTTP which was preceded by Gopher, also younger than the Usenet, which you can already guess by the fact that NNTP is described in RFC 977 while Gopher is first described in RFC 1436.
It has many uses besides filesharing, also have encryption via SSL to hide from nosy eyes. No it isn't perfect, but authorities are always go gonna after low hanging fruit, cause they are the easiest to get to.
You are right with that, but using other protocols, like Freenet (FMS provides an NNTP interface, but there are many other applications), I2P (Forums, Bittorrent, ... ) provide all the benefits while just being a little slower. Also they are easier accessible. Have you ever tried to find an open news server that provides access to binaries? And if you roll out your own with your own groups and stuff, even if you have the money for server, storage and traffic it can be hard to find someone to pull from it.
Again, I think you are right with what you say and NNTP is very nice, but most things can be done easier especially if you want to remain anonymous and/or secure. NNTP wasn't designed for these things. In a lot of Newsgroups nobody will talk to you if you don't use your real name (or what looks like one).