Triangulation - the idea that the deciding political factor was the middle-class political center, which had been captured by Reagan's anti-government rhetoric and anti-labor policies, and therefore, the DP's success would lie in chasing after that elusive center with strongly centrist pro-corporate policies, as the left was already securely in their camp and so no longer needed to be courted.
(Of course, another important factor here was the apparent collapse of socialism as a viable political alternative, creating the possibly correct impression that leaning into anti-labor rhetoric and anti-labor policies would not lose support among the working class any more. We know that this still holds true, as fascism and xenophobia have superseded socialist pro-labor rhetoric as the dominant political rhetorical strategy to garner working class support, and leftist rhetoric has now become the domain of educated
Bildungsbürger middle class and the White urban precariat)