Moreover, how will someone put all their savings into an investment they know nothing about because I would not expect OP to be asking this question if he actually knows one or two things about mining. I would rather just take part of it and buy into bitcoin and hold or just learn how to trade instead.
Nearly everything that people do is based on greed. Important factor is the massive growth of this year, and that's something they try to recreate even at this point.
In order to compensate for not having invested sooner, they will go all in to book larger gains, or at least, that's what they are hoping for. It's basically similar to what happens when people lose with gambling
In order to win back what they lost (in this case earn profits that they missed out on), they go big and bet their entire capital/savings on a potentially good outcome. These people are mentally unstable, and a danger to themselves.