This is totally true. The problem is that because bonds don't trade often, it's hard to make an index ETF based on them. You're basically asking something to be

This is totally true. The problem is that because bonds don't trade often, it's hard to make an index ETF based on them. You're basically asking something to be revalued multiple times a day when the holdings might get their price updated (via a trade) once a week or even once every month.