Look at BND. In January 2008 it was yielding 5.5% and was trading at $78 and over 14 years later today it yields 2.4% and trades at $76.09 in a rising rate environment.
Point taken, but this strikes a bit more of people not understanding what a bond fund is for and paying too much.
I have never owned a bond fund expecting capital appreciation any more than a bond holder would. If you follow enough of these bond funds for a long enough time there seems to be a reversion to a mean or fair price to me. Exactly where that is, not an exact science for sure but anyone who can draw a regression line on a long enough time frame graph can probably get close. We aren't there yet.
I'd be curious on your rolling 5 year CD's to beat most funds data. Looking at last 10 or 20 years I don't see it but maybe misunderstood what you are saying.