look at it this way...
if the federal government abolished the income tax and replaced it with a 30% property tax that didn't exclude your primary residence...
20 years from now liberals would be screaming that homeownership is at an all time low !
People adjust their lives to avoid paying more taxes than they have to, it's a fact of life.
I think Americans have changed where they've put their money however I would not call it savings.
I'd say a good percentage have put it into things of little or no future value which they are convinced have great value.
I'd also say that yes many are putting them into certain investments however I don't see how one could call the potential future returns of a poorly educated investor 'savings'. Most are investing in something highly tied to volatile markets. It's financial suicide to presume returns on non liquid investments are savings.
People used to get pension plans, now they're all getting retirement plans which are held in investments (thanks to ERISA). None of them are getting extra training how to keep that money growing or at least from shrinking. Yes there is value in these plans but I don't agree with modifying the method used to calculate saving to try to account for this value. Nor do I agree with the notion of folks calling that savings, or being encouraged to do so.