I propose a model of a skill-replacing routine-biased-technological-change (SR-RBTC). In this model, technology substitutes the usage of skill in routine tasks, in contrast to standard RBTC models which assume technology replaces the workers themselves. The SR-RBTC model explains three key trends that are inconsistent with standard RBTC models: why specifically middle-wages declined even though routine workers are dispersed across the entire bottom half of the wage distribution, why middle-wages stopped declining while the technological change continued, and why there is no substantial decline in the average wage of routine workers. I derive two new testable predictions from the model: a decrease in return to skill, and a decrease in skill level in routine occupations. I use an interactive-fixed-effect model to confirm both predictions. Since SR-RBTC violates the ignorability assumption required by standard decomposition methods, I introduce “skewness decomposition” to show that SR-RBTC is the main driver of bottom-half inequality trends.