This paper defines a hypothetical Law (HL) of capital accumulation that includes a growth rate of supply of labour force as a non-linear function of capital intensity. The main state variables are the labour productivity, relative wage, employment ratio, and capital-output ratio. An application of an extended Kalman filtering to the US macroeconomic data 19692002 exhibits long wave as a viable pattern generated by capital accumulation. Applying the Structural Control Theory the present paper reveals closed loop control over a fractional growth rate of total profit and its advantages in comparison with an open loop control. The supposed control law of primary distribution of income for the macroeconomic oscillatory system is derived as a substantial modification of the initial HL. It is shown that the US state and business leadership has been pursuing pro-growth stabilization policy with a focus on primary income distribution at least since 2001.