Another estimate of the timing of future capitalist crisis is provided by world-system (W-S) theory. In earlier writing on the capitalist world-system, Wallerstein and colleagues presented a theoretical model of systemic long cycles. The core regions of the W-S in their expansive phase generate their advantage by resources extracted under favorable conditions from the periphery. Hegemony is periodically threatened by conflicts within the core, and especially by semiperipheral zones rising to threaten the hegemon. Eventually the core gets caught up with, just as increasing competition in a new area of entrepreneurial profit brings down the profits once gained by the early innovator; in this respect, the W-S operates like Schumpeter's cycle of entrepreneurship, but on a global scale. With each new cycle, new opportunities for expansion and profit arise, under the leadership of a new hegemon. The crucial condition in the background, however, is that there must be an external area, outside the W-S, which can be incorporated and turned into the periphery of the system. Thus there is a final ending point to the W-S: when all the external areas have been penetrated. At this point the struggle for profit in the core and semiperiphery cannot be resolved by finding new economic regions to conquer. The W-S undergoes not just cyclical crisis but terminal transformation.