(Image credit: Getty Images) For more than six decades, the 60/40 portfolio , comprised of 60% equities and 40% fixed income, served as the baseline for retirement planning. Its success was built on the inverse correlation between stocks and bonds: When equities faced volatility, bonds typically provided a stabilizing cushion. However, recent market shifts have exposed structural vulnerabilities in this traditional model. Persistent inflation, rising interest rates and the increasing concentration of public equity markets have diminished the protective qualities of bonds and the diversification benefits of index funds. From just $107.88 $24.99 for Kiplinger Personal Finance Become a smarter, better informed investor. Subscribe from just $107.88 $24.99, plus get up to 4 Special Issues CLICK FOR FREE ISSUE Sign up for Kiplinger’s Free Newsletters Profit and prosper with the best of expert advice on investing, taxes, retirement, personal finance and more - straight to your e-mail.…