Replicating the dynamics of a failing neon light in a convincing way is going to be a bit more complicated than a simple RNG. It's a bit on the complicated side. If I recall correctly, when in the started mode it's relatively likely to stay that way from a few seconds to minutes, perhaps with periodic instabilities which don't turn it off. Same with being off, wanting to turn on. There's a dynamic to it struggling to flicker on too.
Depends on how much time you want to spend on tweaking it to being perfect, or just using a generic flicker.