The system that allows billionaires to exist is capitalism, however Cortez seems content with the economic system as it is, save for a few reforms. Sad to see that she's just focused on moralising as usual
Wealth inequality isn’t even the primary problem; it’s a side effect. The primary problem is the inequality inherent to the power distribution within capitalism; a system wherein the mass appropriation of labor power, and the “profit” derived from capitalists not paying laborers the full value of their labor (calculated as value upon point of sale). It’s mass theft reinforced through a system of coercive contractual employment (sell your labor or don’t feed yourself/family). So long as the capitalist/proletariat or employee/employer relationship exists, then so, too, will entrenched inequality, a lack of democratic power in a more immediate part of your daily life than government (your job), no control over what you produce (alienation), and countless people being accused of moral failure to excuse the systemic failures of capitalism to meet basic human needs.
Does your view of labor include marketers, administrators, accountants, and other support staff such as janitors and shipping? (In the latter case, the shipping may itself be a product purchased from elsewhere) Do all receive equal pieces of the pie? Do you believe the mandate to split profits equally with any additional staff would discourage certain entrepreneurial figures? How does intellectual property factor into this?