Halliday & Matthiessen (1999: 538):
It might be maintained that a pair of expressions such as in times of engine failure and whenever an engine failed are simply synonymous, and do not imply any reconstruction of experience. But there are two problems with this view.
One is that of history, referred to above. If neither had preceded the other, they could simply be free alternatives (though language is seldom so extravagant with its resources as this would imply!). But since one form of wording came first, it inevitably acquired a rich semantic loading. Since nouns evolved as names of classes of things, anything which is represented as a noun inevitably acquires the status of a thing, with the implication of a concrete object as the prototype. Thus in engine failure, the grammar has construed a thing called failure; and the nominal group then accommodates classes of failure (with another noun as Classifier), such as crop failure, heart failure and engine failure. Thus engine failure and engines fail are precisely not synonymous, because in engine failure the happening failure has acquired an additional semantic feature as the name of a class of things.
The second problem is that of sheer scale. If only odd, more or less random instances of this kind of metaphor occurred, they could have little effect on the system as a whole. But given the massive scale of this shift in the grammar, affecting as it does entire registers of modern English, it cannot simply be dismissed as meaningless variation. As we saw in Chapter 6, the metaphoric processes themselves are highly systematic; moreover they occur in typical syndromes, so that it is not just one aspect of the construction that is affected. Rather, the entire perspective is shifted sideways, so that each element in the configuration is reconstructed as something else. When this pattern comes to predominate throughout a large proportion of the discourse of adult life, it amounts to a fairly major resemanticising of experience.