'Definately' enjoys a subtly different meaning from 'definitely
If some item x is definitely
f (i.e. it definitely
has the property of f-ness), then it must be f in some perfect, absolute, non-finite way.
By contrast, if some item x is definately f then x is f by definition, or is the very definition of f-ness.
The former is an ontological claim, whereas the latter is conceptual/semantic.
That's why all us clever people who spell by rational deduction rather than blind repetition use both spellings, to distinguish our precise meanings.
Of course when they bring the maple syrup after the pancakes, it'll definately be too late.