There is a lot more to the process, according to the site (https://robertsspaceindustries.com/project-status), the persistent universe is not even in a pre-apha currently. Squadron 42, FPS mode, and planetside are the ones currently in a possibly pre-alpha stage (hopefully)). But a pre-alpha means there is something there, that somewhat works. They say that the persistent universe is still in its design stages, meaning its not really in any stage of pliability; possibly even not being worked on but rather working out their ideas and have a game plan. the list would look more like this:
Pre-apha = refers to all activities performed during the software project before testing. These activities can include requirements analysis, software design, software development, and unit testing.
Alpha = A very early version of a software product that may not contain all of the features that are planned for the final version.
Beta = A beta is software still under development that is made available to a select few to test, examine, and report problems they face. Beta testing allows developers to find problems they may have missed and fix them before the program is released.
Release = Generally all the assets are at the slandered the developers approve of and all features are in that they feel necessary.