[does happen, will happen], [go, will go] - notice that the active verb doesn't change from present to future, rather there is an auxiliary added to mark the tense. Contrast to French where you have [vois/see, verrai/will see] and the verb itself is modified.
Right, English doesn't have a future tense (in the sense of tense as marked by inflection). So what's the contrast of note? That the one sentence marks the future by use of a modal auxiliary (in addition to the explicit "tomorrow"), while the other marks the future only by explicit description of the time "tomorrow"? Mark me as highly skeptical that this is of any significance...
I'm saying it's a strange example to say that some languages do or don't have a grammaticalization of time, and then give two supposedly contrasting grammars as an example of each, when actually neither of them really has a future tense.
It's obviously got at least one word for the future ("tomorrow"), which is kind of like having a library function strcat instead of just +
Also, English doesn't have a future tense, so there's that.