The obvious answer is that Rudyard Kipling does not treat negative consequences at all in his poem "If." The poem begins by setting up a series of conditional statements. Logically, the first three stanzas and the first six lines of the fourth stanza constitute the protasis of an extended conditional, and the final two lines of the last stanza the apodosis of the conditional.
If the addressee succeeds in fulfilling the conditions set forth in the protasis, the ensuing results will be:
Yours is the Earth and everything that’s in it,
And—which is more—you’ll be a Man, my son!
If the conditions are not fulfilled, the Earth will not be the reader's nor will everything that is on it and the reader will not be a true "Man" by the standards of the poet. The poem is not, however, really concerned with negative consequences, but is more an effort to paint a picture of a model that a young reader should strive to emulate.