Once upon a time, America’s workplaces were cozy places of racial homogeneity. Sameness was good, difference was bad.

Then in 1963, the largest number of protesters ever to assemble in D.C. up until that time marched in the hot August sun demanding not just the dream of freedom, but the reality of good jobs for African Americans.

Women, Latinos, people with disabilities and the LGBTQ community all joined the fight for inclusion by demanding the banning of discrimination in private and public employment. Diversity broadened to be about race, gender, class, sexual orientation, age and even thought.

Angela Glover Blackwell, founder in residence of research org PolicyLink, has a mission to advance economic and social equity and is a national voice for equity. She likes to tell a story of bike lanes — how New York started addressing the concerns of bicyclists, an overlooked minority, by installing bike lines. Not just one or two here and there; miles and miles of bike lines were developed. And here’s where Blackwell explains the aha moment.

The result benefited not just the minority group of riders, but also pedestrians, the much larger group. For example, the risk of serious injury to bicyclists dropped 75 percent but it also dropped 40 percent for pedestrians. Her point: the unintended benefits of inclusion.

The benefits of diversity and inclusion has filled volumes, but it still faces an uphill battle for complete acceptance. For Generocity’s last feature of Leaders of Color Month 2018, we asked local leaders of color to weigh in with their stories on diversity and the consequences of exclusion.

Without diversity, your potential labor pool is too small.

Ask Rashida Perry-Jones, director of policy and communications for SELFInc, which runs homeless shelters in Philadelphia.

“I’ve worked in the arts community, been a labor organizer and worked in nonprofits,” she said. “Diversity is the key to success. … Corporations need to take a good look at what America looks like and ask themselves, ‘Does your workforce and leadership team look anything like this?'”

Sameness creates groupthink and groupthink limits the ability to creatively problem-solve.

So says Kellan White, chapter director of New Leaders Council, which recruits, trains and promotes the next generation of progressive leaders.

“The same experiences create the same solution,” he said. “About five or six years ago, I began to diversify our board. It had been primarily composed of white men.”

The end result: a stronger program, stronger candidates and a better recruitment process.

“Diversity of thought improves the product,” White said.

Exclusion depresses earnings.

That’s according to Greg DeShields, executive director of PHL Diversity within the Philadelphia Convention and Visitors Bureau (PHLCVB).

Diversity is a growing industry: Since 2015, PHL Diversity has hosted more than 114,000 attendees at its diversity-related events for the PHLCVB, resulting in a three-year compounding effect of $100 million in economic impact, he said.

“Diversity in the workplace is about two things: thought and perspective,” he said. “Diversity of perspective requires self-awareness and this leads to diversity of thought.” (This is why DeShields has 62 people on his advisory board.)

Where there is exclusion, there is trouble.

Ask Robyn Forman Pollack, founding CEO of Trellis Consulting Firm, a business strategy firm with a focus on diversity and inclusion.

“If you have a diverse and an inclusive organizational culture, you are able to attract and retain the best talent and clients, and avoid diversity crises,” she said. “Lots a people call us reactively such as when they experience a law suit — an Uber or Starbucks situation, a PR problem, a mass exodus of a diverse constituency, people are badmouthing them on Glassdoor, or they are not awarded investor financing. Instead, they need to be proactive because it’s much harder to come back [after a problem].”

Diversity requires care and feeding to thrive.

That’s what Kimberly Reed, a diversity and inclusion strategist and certified diversity practitioner who founded Reed Development Group, says.

“Diversity and inclusiveness will not be sustainable if it is not in the company’s DNA,” she said. “When companies treat diversity initiatives as a corrective action, as punitive, they create an environment of isolation. Diversity is not that. Diversity is a business imperative and to be sustainable, it has to be part of the fabric of who they are. If you have all the same people, then your business is one-dimensional and it isn’t going to grow.”