What retirement? Americans will have to work longer, we've been warned.

Fewer companies guarantee pensions. With more old people to maintain, Congress is weighing plans to limit Social Security and Medicare, raising qualifying ages, and curbing benefit increases. "Our big entitlements are going to have reform so they are there for the next generation," as U.S. Sen. Pat Toomey (R., Pa.) warned recently.

So keep working. But where? For a lot of managers and salespeople, already used to having to switch jobs and projects every few years, opportunity slows with age, leaving the future foggy.

"I did not realize myself until I reentered the job market" how tough it is for older business people, says a man we'll call Irish Bill, who lives in northern Delaware County. Bill, who is 62, asked that I keep his last name off his story because he's still tangled in confidentiality agreements from his former career.

"I have over 40 years' experience in construction financial management, construction management, and commercial real estate management and development," Bill told me. "About a year ago, I concluded an engagement, as a consultant, with a large financial institution that had almost $200 million in bad construction and development loans. They brought me in to finish and sell this distressed portfolio." The project had taken four years.

He moved the properties, then "took a little time off, and decided that instead of trying to resume my consulting practice, I would explore employment situations where I might be able to use my vast experience to assist a younger operation that might value it."

But when Bill went looking for his next stop, he realized he'd crossed an invisible line — of age, time, some indefinable barrier that locked his career into the past.

"Boy, were my eyes opened," he told me.

First, he went to an executive recruiter, who "informed me he was not in a position to try and help me. When I asked why, he informed me that placing someone over 50 was extremely difficult, but someone over 60 was almost impossible. In fact, he informed me that, should he present me, he would probably lose that client and most likely his job."

Next, he tried a professional-staffing firm to fill a construction-management opening. Based on his resume,  he recalled that the staff told him "I was the best candidate, with unbelievable experience and a great fit."

Bill was encouraged, despite the low pay offered. But the clients "felt that I was overqualified. They were afraid of me finding another opportunity and leaving in the middle of the project. I offered to sign a contract which would alleviate those concerns." No reply.

Then he fell "about as low as one can go": the job message boards. Bill answered requests for project cost-accountant positions — "basically, starting over." No replies.

Plan D: "On Monday, I am attending an open house at a recently opened hotel that is looking for a shuttle driver for their guests." He hoped to get lucky and find an airport route, and passengers who tip.

Can't people who work hard find something that pays into their silver years? I put the question to  a couple of guys who are Bill's social and job contemporaries. "He's not a whiner. He's right," said Jim Horan, 65, another commercial-loan-workout veteran, who last worked full time in 2013. "Over 60, you are a Dead Man Walking in the job market."

"It happened to me," says Greg O'Meara, 67, a former bond trader who now sells Irish bread from a Delco bakery. He remembers a recruiter turning him down obliquely by showing him a stellar Wall Street resume from another bond trader. "It was very good. But he was 57. He told me, 'This guy will never get hired in that industry again.' "

Unlike jobs where seniority counts, there's no tenure on Wall Street — or in sales, generally —  it's all about your perceived ability to keep selling, added O'Meara.

"You eat what you kill. Some industries pay great sales commissions. Some years, the game was aplenty." In fat times, people come to "associate their paycheck with their confidence," he said.

Then the game ends. When O'Meara lost his trading job in the recession, "I sent resumes to at least 50 places, and the response rate was quieter than two butterflies on top of a lemon merengue pie. If you are over 50 and reduced to digital contact, you are dead." He added: "I don't think the Boomers saw this coming."

The high-end gig economy has developed at the same time as guaranteed pensions have nearly disappeared, except for top management and government workers. O'Meara says we could write "a sad book" with all the stories, but the subjects couldn't afford to buy it: "They're driving Ubers, and shuttles, and working as security guards."

Bottom line, O'Meara concluded: "When the game gets scarce, and compensation diminishes, well, you had better have something set aside."