I feel that this is not surprising. The great majority of mutual fund buyers look only at the most superficial and often misleading metrics. The fund firms are behaving rationally, by attracting the most money that they can while staying within the law.
You wouldn't believe how little some investors understand about mutual fund payouts vs.those same funds true yields.
In fact, to me the way the TIPS funds report is less misleading than the typical way that mutual funds like GABUX and many others combine actual dividend and interest income with return of capital in their popularly reported yields. In the case of GABUX, the revelation that their actual yield was roughly 15% of their reported yield came only in near the end of the annual report.
If I understand you correctly, at least with the TIPS funds you are discussing, it is a yield, but it is not the "real" yield.
I am coming around to the idea that for the great majority of investors, they should buy a good selection of funds from Vanguard and then go play pinochle.
Anybody should understand that a fund cannot yield more than its underlying securities, in fact it must yield less, the amount less depending only on the size of the drag from the costs. So if no TIPS security yields anywhere close to 6% real, how could the fund?
If one is not prepared to think even a little, he should stay home.