That doesn't explain just goku that pretty much explains comic/manga in general,but the thing is everybody knows this already....and for the record the highest form is Super Sayian 3 and it still got owned by buu...so you're kinda missing with that,and Super Sayian Gogeta is technically the strongest(GT isn't canon so technically Super Sayian 3 is the highest level).....we'll have to see how this new villian bils fairs.
n*gga just took it to Super Nerd level 3 on my a.ss
highest level ever? and
still owned by buu? and
this bils n*gga is the strongest in the db universe? well...... get ready for a brand new level of kickass for goku to level up to
but i get it, you could make the same argument for superman and others. except...
there are superheroes with clearly defined abilities that don't miraculously expand...all i'm sayin...
and i haven't even watched too much dragonball. but i've seen enough to know goku bores the fu*k outta me and i think the writers that created him were lazy and uninspired for it.