Over the past 100 years stocks have outperformed bonds by 10% versus 4%. For 40 years interest rates fell and bonds returns were 7.5% versus stocks at 12%.
In the last 5 years as interest rates started to rise bonds had a return of (2)% versus stocks at 12%.
As you can see bonds underperform the S&P by a substantial amount even in falling interest rate environments. The only time bonds outperformed was during the lost decade where stocks had two 40% market corrections and the Great Depression.
The only logical reason to own bonds is you think the market is going to have a large correction. Since nobody can consistently call market direction, that is not a good reason.
Financial advisors recommend bonds should be in your portfolio so that it is diversified. The objective is to dampen stock market drawdown. This does not appear to work very well. As you age financial advisors recommend about 40% bonds in your portfolio. For long term investing bonds hurt portfolio performance because there is a lost opportunity cost of at least 6% per year or 2.5% on your whole portfolio. With the Stars strategy the lost opportunity cost is about 20% per year. In 4 years you lose more than a major correction.
Long term interest rates are likely to rise because of the high debt levels. In that environment owning bonds makes no sense.