As I understand it, Level 5 is basically just given a budget for whomever publisher hires them for a specific project. It doesn't matter to them whether the game sells or not since every Level-5 employee get their normal salary anyway. What matters is if publishers give them projects to work on. I see level 5 as workforce contractors.
At least this is how Platinum Games are structured. Level 5 could be different for all I know.