As others have pointed out, bonds are barely (or not) keeping up with inflation. I would like to suggest a third alternative to stock index and bonds: stable dividend stocks. They should increase in value along with inflation but still pay out a steady dividend as long as the company is strong.

With the big caveat that strong dividend yields can be an indicator that the market is considering the company to do poorly in the future.

Buy inflation linked bonds? They won't yield much above inflation but if you have >1M that's enough to last through retirement.