There is a dark side to South Korea's 50-year rise to riches: The greying generation that is most responsible for that ascent is living in relative poverty.

In a fast-paced nation famous for its high achievers and its big spending on private tutors and luxury goods, half of South Korea's elderly are poor, the highest rate in the industrialised world.

Some live in crumbling hillside neighbourhoods that lack running water. Others wait in line at soup kitchens where there is no young face in sight. The worst-off comb through garbage, collecting cardboard and paper and lugging it to rubbish dumps, where they can receive several dollars for a pile. It's common in central Seoul to see elderly people gathering scraps.

Most of South Korea's ageing poor were comfortable or even prosperous during their careers, experts say. But they have tumbled backwards since retirement, victims of a tumultuous change in the way this nation treats its old.

In much of Asia, a powerful Confucian social contract has for centuries dictated that children care for their ageing parents. But that filial piety is weakening as younger generations migrate to cities. The change is particularly noteworthy in South Korea, because it has accumulated wealth so quickly and its society is so notoriously cut-throat, with ruthless competition for the best test scores and more prestigious jobs.

"It's almost like people don't have the psychological space to care for other people," said Lee Sun-young, an administrator at a senior centre in the Seodaemun district of Seoul.

Over the past 15 years, the percentage of children who think they should look after their parents has shrunk from 90% to 37%, according to government polls.

Meanwhile, South Korea's government has been slow to provide a safety net. Only a third of retirees have pensions, and the payouts are relatively paltry, analysts say.

"The family has crumbled," said one retiree in Seoul, Park Jang-su. "That's why we are dying alone."

Increasingly, the mix of neglect and weak government support is turning deadly. South Korea's elderly suicide rate has more than trebled since 2000, a surge that has occurred despite counselling and awareness programmes funded by local governments. At the senior centre in Seodaemun, a district where some 9,000 elderly people live alone, three staffers run a suicide hotline. They take about 30 calls per day. Ten workers go door to door through Seodaemun, trying to find and help those who are "dangerously isolated," said Lee, the administrator.

On a recent round, Yang Yun-kyeong, 24, one of the staffers, packed her car with several boxes of flavoured milk, a foam carton of kimchi and a sack of sticky rice. Over the afternoon, she visited seven homes, making deliveries to those either too ill or poor to buy the goods.

One visit led her to a darkened apartment building with cracked windows and Xs painted on the doors. The building had been condemned, but five units were occupied. One belonged to Lee Yeong-sun, 82, who lives with his wife, who is suffering from dementia.

Lee welcomed Yang inside and invited her to sit down. His floor was covered with quilts and heated only by an electric blanket. The apartment smelled of mould.

Lee had served in the Korean war and worked a variety of odd jobs in the following decades. He doesn't have a pension. He lives on roughly $300 per month, he said – payments from a veterans group and a government welfare fund. His main hope, he said, is to stay alive longer than his wife, so he can continue to take care of her. But he has trouble getting her things she needs, because he doesn't like to leave her alone for more than two hours. His two children lend him no financial help, and one doesn't answer his calls.

"The worst part is the loneliness," Lee said.

South Korea established its pension system in 1988, too late to benefit those like Lee born before or during the war years. There is a welfare system, but its laws are antiquated. Those with children are ineligible, unless they prove their offspring are unwilling or incapable of providing support. Many elderly people don't pursue that exemption because they are embarrassed about their situation.

Even those who had good jobs have fallen back into poverty because they spent heavily on education for their children and saved little money, figuring their kids would provide the care they'd need as seniors.

South Korean President Park Geun-hye pledged during her 2012 election campaign to improve welfare programmes and described a "National Happiness Pension" worth an extra $200 per month. But she was never clear about the funding for her programme and was reluctant to raise taxes. Several months ago, the president scaled back her plan in a controversial move that prompted the resignation of her health minister. Only the poorest 70% of seniors, as opposed to all of them, will receive the new payouts beginning this summer.

For those like Lee, the additional money will make a small difference. For years he has taken extreme measures to limit his spending. To buy medication for his wife, for example, he occasionally takes a 50-minute train ride – free for seniors – to the outskirts of Seoul, where a pharmacy has slightly reduced prices.

During Yang's visit, Lee apologised that he couldn't offer her any food, and he told her a story about the years just after the Korean war, when South Korea was in ruin and the gross domestic product per capita was less than $100. "Back then," he said, "food was so scarce that people didn't ask, 'How are you?' Instead, they'd ask whether you'd eaten.

"Now," he said, "I'm worried about running out of rice again."

This article appeared in Guardian Weekly, which incorporates material from the Washington Post