Well the hulk's mutation, like superman, included the ability to withstand its effects. Even though the mutation happened at a later time, it's still a mutation, although I suppose we could discuss what a mutation is. In my mind the actual DNA must be changed in order for the change to replicate for new cells.
Further, the mutation must happen in a way that doesn't trigger an immune response, it must spread to all the body, and must do so quickly enough that, for instance, half the muscle doesn't become super strong and rip apart the other half that hasn't changed yet. It can occur instantaneously, or while one is unconscious. It's more likely that one would become terribly ill, fall into and out of sleep or a coma, and then awake completely changed, having survived the mutation, or died in the process.
Then we have to talk about the various changes that must exist for any one power to manifest. Take the laser vision guy, for instance. Oh no, suddenly everything I look at starts flaming or exploding! My eyelids can magically withhold the power. Wait, what? So you are 1) able to produce a coherent energy beam measured in the kilwatts worth of power, and 2) it can't pass your skin, and/or you can turn it on and off with your mind, it just happens to use the same signals your eyelids use? Don't even get me started about the glasses he wears - they have to be able to convert the energy of kilowatts of power, continuously, into something benign. It can't be heat, or he'd have cooked his head long ago. While that's a science fiction question, you have to think about the same thing with his eyelids, therefore for this to work his body must also be able to absorb a huge amount of radiation through the skin and convert it into something benign.
To be useful and usable, and not kill you, seems to require a sequence of events and changes that together give you your power - any one part of it alone would be useless or destroy you.
Besides, even in your example of rich being the best superpower, there are untold millions of stories of sudden wealth destroying people. I'd say that still follows the theory that sudden superpowers are also self-destructive in general.