To be fair, anybody can come up with $100k to buy a position, knowing they can sell it on easily enough if they want to back out. In almost any such project there is a cost escalation and the position buys you a fixed price (usually) which is where the investment value lies. Consequently there is a huge speculative element in this kind of thing.
I don't think the world has changed. What has mainly changed is that people are not so stupid as they were when Rayburn was taking deposits
Most of those who took positions didn't have a clue about aviation or aircraft; if they did they would have realised the project was infeasible at the original price levels.
Maybe in 20 years' time one will be able to do another large scale con...