Maybe zombiewager is a legit one but happened to have no chance of proving itself in this industry because of lack of popularity. Stake is now one of the most popular gambling sites in this industry aligned with the biggest ones. The way of introducing a gambling site in this industry would surely vary. These two gambling sites had different outcomes even if they are both introduced in the market at the same time. Stake have been promoted in different mediums which have established wide popularity and  reputation, which also, in the latter, have built a trust from this industry. I've checked the site of zombiewager, it is working but I've heard that they would again run this project, maybe, they are waiting for a follow up, at the right time which is a good idea. People are just into gambling sites which are popular, this also, takes the opportunity for the new ones to be tested by players.
We cannot blame those players who are avoiding new and unfamiliar projects because there are fraud gambling sites which are mostly those that are not recognized by many players. I know some players who became a victim of such problem. It really did serve a lesson for him to just stick with the big names in this industry. Such a safe thing to do but I just feel sad to the new gambling sites of this industry to shine.