“We’re too big and complicated a system to do anything in reaction to a particular group or something happening,” Karen King, who has the wonderful title of “chief people officer” at McDonald’s, said Wednesday, explaining her company’s decision to raise wages for some of its employees.

If you believe that, don’t go near anyone purporting to sell you a bridge, even if it comes with fries on the side.

The raise at McDonald’s, even though it applies only to a small fraction of the employees who work at the Golden Arches, is one of a series of remarkable, if incomplete, victories that low-wage U.S. workers have won in recent months. It follows announcements from Wal-Mart, Target and like establishments that they’re raising pay for their poverty-wage workers. It also follows minimum-wage hikes enacted by voters and elected officials in numerous cities and states. And it reflects the broad support in poll after poll for raising the federal minimum wage from its abysmal $7.25 an hour.

Part of the workers’ success is due to the improving job market, which gives workers more leverage. Part of it is due to the domino effect of corporate raises: If a worker can make more at Wal-Mart than at Target, why work at Target? Part of it is due to the better performance that more highly paid workers turn in. “Motivated teams deliver better customer service,” McDonald’s chief executive, Steve Easterbrook, told the Wall Street Journal in explaining his decision to raise wages — by which logic, however, it would surely make sense for McDonald’s to mandate a raise, as it mandates so much else, at its franchises.

But the prime mover behind these raises, whether company-specific or legislative, is the workers themselves. The campaigns of the fast-food workers, Wal-Mart employees and others have functioned as a kind of second act to the Occupy Wall Street movement, not just highlighting the enormous disparities of income and wealth in our society but also putting forth a concrete demand, as Occupy never did, to remedy some of inequality’s most remediable extremes.

In a sense, what these workers have created is a form of collective bargaining by other means. With the ability to form unions effectively blocked by the weaknesses of the National Labor Relations Act, which employers can and do violate with impunity, workers have crafted other ways to advance their interests. Particularly crucial has been their growing political power in America’s cities, which, as never before, have become the nation’s liberal power base. It’s cities where immigrants have not only flocked but also organized and won political power, cities where left-leaning millennials have chosen to live, cities where African Americans have maximized their political clout, cities that have begun enacting municipal wage hikes and paid sick-day ordinances, and cities that use their purchasing and regulatory powers to compel private-sector employers to treat their workers decently. Today, 25 of the nation’s 30 largest cities, including many in red states, have Democratic mayors, and this partisan imbalance is in many places the consequence of the political organizing of low-wage workers thwarted by the NLRA’s weakness and employer opposition from organizing their workplaces.

There are limits, however, to what this kind of organizing can achieve. A more egalitarian economy requires a more egalitarian balance of power — which is why the only time in U.S. economic history when a rising tide really did lift all boats was in the three decades following World War II, when unions were sufficiently large and powerful to compel even non-union employers to match their wage scales. States and cities can raise the minimum wage and the Wal-Marts and McDonald’s can hike their pay, but these moves, commendable though they be, don’t significantly alter the power imbalance hard-wired into our current economy. That still requires the legal ability to form unions — a goal that eludes workers in our plutocratic age.