Large technical systems subject to a rapid rate of technological progress, such as fixed line and wireless electronic communications networks, give rise over one or more decades to successive generations, each substituting its precedent, as for mobile telephony nG after (n-1)G or optical fiber following copper in fixed telephony networks. This process prevails for many networks, including transportation and energy, when observed at a proper scale of time. This paper builds a simple geo-economic model of the socioeconomic impact of a transition from an existing technical generation to the following one, as regards : (i) accessibility provided to populations within various territorial areas of differing demographic densities ; (ii) the socio-technical divide separating adopters from non-adopters of the last available generation ; (iii) the systemic dependency generated by the irreversibility of the technological transition. Taking the spatial variability of connection costs into account, the model shows that the optimal roll-out of a new technology may consist in not covering the most remote areas, provided that the preexisting technology there is resilient enough or may be upgraded or replaced by an alternative technology the cost of which is not significantly dependent on distance, such as satellite in the case of electronic communications. The originality of this approach lies in a marriage of economic and geographic concepts in the construction of an elementary model which sheds light on the stakes arising from the joint action of engineers and territorial planners along the path of technological renewal.