New Brevoort Formspring

How can you consider Thor, Superman or other such characters to be as "becoup powerful" as Hulk, if Hulk potential strenght is limitless and it's established as such continuously for the last 50 year, while the Others haven't been established likewise with such regularity, and have been "pushed to their limits" more than once? shouldn't Hulk then by definition be more powerful than anything in the Marvel OR Dc universe?