GoFundMe campaigns have been raising piles of cash for older Walmart workers who want to retire — but the heartwarming stories about sudden windfalls mask a dark reality about economic security and growing old in America, say retirement experts.

“This is not a feel-good story, this is about the failure of our retirement system,” said Teresa Ghilarducci, a labor economist at the New School, about the spate of GoFundMe campaigns supporting older Walmart workers.

‘Stories of strangers helping elderly workers’

Fundraisers…