The 105-year old car company is an iconic American corporation, and the automotive industry is tied to notions of traditional masculinity more than other sectors.

But does Barra’s elevation signal a transformative change in the auto and manufacturing sectors? Or is it an anomaly that merely gives the illusion of progress for women?

The answer to both questions may be yes. Prominent women executives highlight the symbolic importance of having a visible female executive to inspire and mentor lower-ranked women, and to counter the unspoken assumption in many minds that a woman couldn’t fill a C-level position.

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“There’s no doubt there’s a dearth of women in leadership roles at publicly traded companies,” says Kim Bowers, CEO of CST Brands, one of North America’s largest convenience retailers. “It takes time in the seat to move into a C-suite role. Industries that start out typically male will take longer [to change].”

A look at a recent report by Catalyst turns up data relevant to the questions at hand. First, there’s the discouraging reality that, for the fourth year in a row, 14.6% of Fortune 500 CEOs were female. Board progress has stalled even longer — no significant change for eight years, with women holding only 16.9% of corporate board seats in 2013. Women occupied only 8.1% of top earner positions, representing no change from Catalyst’s 2012 report.

But looking closely at the most and least male-dominated industries reveals counterintuitive findings. The five sectors in which women have the strongest chance at advancing to CEO are retail-trade (18.6%), finance and insurance (17.6%), oil and gas (16.9%), science and technology services (15.5%), and nondurable goods manufacturing (15.2%). You might not expect to see finance, energy, or technology on that list.

The five sectors where women are least represented in the C-suite are construction (4.3%), arts and entertainment (6.3%), management (6.9%), real estate (9.5%), and durable goods manufacturing (11.2%). Once Barra (who was No. 29 on Fortune’s 2013 Most Powerful Women list) takes on the CEO role at GM, that durable goods manufacturing number will tick up only slightly.

The fact remains that the highest percentage of female CEOs — 18.6%, in retail — is rather low given that more than 50% of college and advanced degree earners are women.

“We haven’t made a lot of progress, in my opinion. There’s a lot of holding and gating factors,” says Gay Gaddis, CEO and founder of T3, an Austin-based digital agency, who says she has often been the only woman in a room of high-level executives. “A lot of companies will say, secretly, we’ve got two potential candidates: the woman and the guy, both qualified, but better bet on the guy because we think he’ll follow through. We think he’ll be willing to stay later at night if we need him to.”

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It’s unclear if Barra is part of a new wave of women CEOs who will pave the way for a new generation of female leadership in male-dominated industries — or simply an outlier. Women held only 24.2% of all automotive manufacturing jobs and 16% of executive or senior level positions in 2012, according to Catalyst. And the broader numbers tracked by Catalyst certainly paint a picture of stalled progress in the last decade.

Bowers believes that women will eventually break through, as the millennial generation advances to middle management and eventually takes over top roles.

“All these male-dominated industries — be they tech, finance, or automotive — would do better with more women,” says Sharon Meers, a former managing director at Goldman Sachs and co-author of Getting to 50/50: How Working Parents Can Have It All. “The research proves out that when you have more women in the room, you have better decision-making. It’s just a fact.”