Classically, the introduction of new technologies is often described as following an S-curve that assumes uptake is initially slow in the earliest stages prior to a dominant design emerging, until performance and functional benefits of the new technology are seen to be greater than those of existing technologies, at which point uptake significantly accelerates \cite{richard1986innovation,utterback1994mastering}. This model assumes that eventually all technologies then arrive at a limiting condition where they too begin to stagnate as uptake reduces (potentially due to market saturation or competition from new technologies), with substitution to a subsequent generation of technologies occurring either before or after arriving at this temporary plateau (see Fig. \ref{402288}). This brings about the notion of continual technological (or functional) failure, at the point where a replacement technology is sought for the current technological paradigm. However, the technological 'failures' that lead to this type of substitution vary greatly, and cannot just assume a single simple definition. In this regard, previous work has examined what is meant by 'technological failure', and has broadly categorised these occurrences into three main definitions \cite{Gooday_1998}:
- ‘Failure’ as a social taxonomy of marginalised technologies: ‘Failure' is not an essential characteristic of the technology itself. Instead 'failure' depends on a diverse range of usage factors that may not be replicated in other cultures, and is chronologically bounded so that any given technology can be classed as a success or failure at a given point in time according to social responses to it. This definition implies that ‘failure' is a completely unexceptional matter in technology, and that all 'successful' technologies 'fail' at some point in their existence \cite{Gooday_1998}
- ‘Failure’ as a mundane feature of technological usage and development: Persistent 'failure' of technology is an unavoidable consequence of ever more demanding expectations that human users impose upon their all-too-limited constructions. As such, what 'fails' is human expectations of hardware performance and distribution - or rather a 'failure' of socio-technical relations \cite{pye1978nature,Gooday_1998}
- 'Failure' as a perspectival and often contested attribution: many recent sociological studies of technology employ two simplifying assumptions; firstly that there is a decisive closure point in history at which a technology is judged a 'success' or a 'failure', and secondly that at this point in time, all parties come to a decision that is ultimately consensual, despite being based on differing perceptions of the technology's social role. Both of these assumptions can be challenged by strong counter-arguments \cite{Gooday_1998}
In the analysis that follows, this study focuses on the first of these three conditions (whilst the other two are addressed to a greater extent in separate technology adoption modelling work). Specifically, the definition of technological failure used in this study is given as:
“A point in time at which technology performance development stagnates/plateaus, with no further progressive trajectory improvements foreseen for a significant period of time in comparison to the overall technology lifecycle considered, which is subsequently followed by the substitution of a new technology/architecture that is on a progressive trajectory”
This means that a technology has been able to reach what could be observed to be a temporary performance limit in this condition before substitution to a new discontinuous technology occurs \cite{Schilling_2009} (i.e. see left and right images in Fig. \ref{402288})