Must all revolutions necessarily fail?

Note: such a question might appear in a humanities subject aptitude exam or interview. The following answer presents what I would consider a viable approach to the question.
INTRODUCTION History is pinpointed with moments that have grown to be known as “revolutions” (hook). The word alone elevates the events' significance to the modern observer; the word "revolution" carries with it the underlying judgment that radical changes was brought about to the status quo. In light of this, the failure of such events is a rather elusive concept: revolutions in their nature might be unable to fail. This is, firstly, because of the way in which they introduce new ideas into society and serve as turning points (even if, practically, as it is the case with the 1848 European revolutions, they do not seem to yield many successes at the time in which they occur) and secondly because of the way in which they are viewed – the perceived importance of historical revolutions in the present means they are necessarily successful to a certain extent. If the aim of a revolution is to achieve a broad reach change (even if this is largely symbolic) then, in hindsight, its presence in the collective conscious of a group demonstrates it has to some extent achieved that. 
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Paragraph 1 – revolutions which impacted the way in which humans live collectively and organize themselves ·      Agricultural Revolutiono  Nature: move from being hunter-gatherers ·      Industrial Revolutiono  Nature: Capitalism (change in terms of an economic model), allowed for social, development, urbanization ·      Counter-argument: both of these revolutions had adverse effects (the agricultural revolution’s adverse effects can be seen more clearly because of how long ago it happened)o  Agricultural revolution à o  Links to the idea that in the long term, all revolutions MAY necessarily fail – we just haven’t lived long enough to see it yet (e.g. o  HOWEVER, these impacts don’t make revolutions a failure! They achieved change in the way in which people live
Additional debate: do revolutions need hindsight in order to be termed as revolutions?
Paragraph 2 – link to p.1 – can be quite appealing to call historical revolutions a failure but their social impact is immense (particularly in terms of more recent ones) and their symbolism grows to be viewed as a ‘turning point’ ·      Historically appealing to call revolutions failures but when one looks at wider themes, their symbolic impact means they live on – change has been achieved at least in some part ‘of the equation’·      Carnation Revolution in Portugal·      French Revolution + 1848 liberal revolutions ·      Rwandan genocide as a revolution ·      Link: what matters more (the ‘reality’) or perceptions of reality? à perceptions of the Carnation Revolution in Portugal
Paragraph 3 – significant modern debate over current ‘revolutions’ demonstrates the fact that the nature of revolutions isn’t black/white or failure/success (so multifaceted that they can’t possibly be)·      Technological revolution/social media revolutiono  Should these be termed revolutions? (Revolutions typically implicate a change to political power and to some extent, these are achieving that, e.g. fake news, rise of Trump) o  Dichotomy between big brother/real over privacy vs. wanting institutions to make changes and get involved in discourse ·