I figured L-5 Society and similar space "fanatics" weren't serious. If they were serious they would have been working on getting to space, not jawboning, mostly to each other, about how important it is and how they need to get the government to spend more money on it or to do it.
Most of the cost of getting to space is spent on the people who do the work (except for bureacracy costs in NASA, that is). If the "space fanatics" had actually been willing to work at it, and cooperate and do the work themselves, they should have been able to build decnet quality rockets and start actually putting people into space. Instead, they all just sat around talking about how important it was to get someone to pony up the money for it.
And before someone starts talking about the space entrepreneurs, they were just a bunch of underfunded companies, trying to do "demonstration" project to get more funding. They weren't even trying to actually start a serious business of getting to space. To be fair they didn't have the resources for that anyway. But "space fanatics" as a group probably did have the abilities and resources needed, if they could work together and do it.
The closest anyone has come is Robert Zubrin, author of Entering Space: Creating a Spacefaring Civilization and The Case for Mars: The Plan to Settle the Red Planet and Why We Must. And most of his work was the cheaper problem of using Martian materials and was paid for by his aerospace employer. Unfortunately, the Mars Direct bunch is just like the earlier L-5 Society, instead of getting together to work, they're just getting together to whine.
In reality, they are just another version of welfare liberals who want the government to pay for what they want.