The plasma focus can and has been reproduced many times. The problem is the LPP has a patent or two on the technology. The patent owners have the rights to the technology so even if it is easy to reproduce no one else can do it and make money or produce products such as reactors. You can hate the patent system but it is the law. The patent owners would surely fight hard to protect this breakthrough for the duration of the patent. These is also the issue of others patent on parts of the technology. Several groups own patents on different aspects of the plasma focus. They worked hard on their pieces and will want some of the pie when the time comes.
When fission was first commercialized the strategy was that electricity would be so cheap they would give it away. That ideal was never realized. FoFu is likely to have the same fate. The technology will be locked down by patents and sold to the highest bidder. If one group or company buys up all the relevant patents and people the energy future is owned by that group.