Involving more people into creating relays: bittorrent-like reciprocal routing
We all know that people have suggested ways to make Tor not so reliant on altruism, and one of the biggest of them is torcoin. But I have an idea that doesn't require passing a huge blockchain structure around or any of the other things associated with cryptocurrency overhead. It's called tit-for-tat, the same thing bittorrent uses.
Basically, the suggestion is, if you use tor, you can become involved in routing packets (by default only as a routing node, unless you specifically take up being an exit node). Your efforts are repaid later when the people you've helped route packets from are much more likely to help route your packets in return. This suggested system is much like bittorrent, where helping other users retrieve the file they're trying to download will help you download more stuff from them immediately or later on. While other peer-to-peer networks have fallen into relative obscurity or collapsed, bittorrent remains very strong, partially because of tit-for-tat.
The current altruistic nodes can continue being there to help relieve demand bottlenecks, but with reciprocal routing, the tor network can scale up farther than if we continued to rely on altruistic people to run nodes.
If you still have no idea what I'm trying to say, check out tribler. They're building a tor-like network into their bittorrent client as I type.