In this work, we propose a new model of product evolution that explains the emergence and displacement of dominant designs from an engineering design perspective. We identify the gap between user-demanded usability and the usability provided by existing product solutions as the primary driver of product evolution. Building on the distinction between conceptual and embodiment design, we introduce the novel paradigm of concept elasticity, which describes a conceptual design’s inherent potential for usability enhancement through the optimization of its embodiment design. In contrast to existing frameworks, we do not view technological discontinuities as the primary trigger of disruption but rather as its vehicle. Instead, we argue that reaching the limit of a dominant conceptual design’s elasticity marks the transition to an era of ferment, which ultimately leads to the displacement of the existing dominant design. Using a qualitative case study approach, we apply our model to timekeeping pendulums in observatory regulators. Our findings demonstrate that the model effectively explains the design trajectory of these clocks, particularly the emergence and disruption of dominant designs over the past centuries.