We haven’t been hearing much lately about retirees facing severe financial hardships. Personal investment portfolios have rebounded with the stock market, home prices are up, pension plans are somewhat better-funded than a few years ago, tax reform didn’t cut Social Security, and active retirees often can pick up part-time jobs if they want, amid a strong economy. But the future doesn’t look as promising, with several forces likely to increase the financial “fragility” of people planning to retire years down the road, especially younger Baby [...]