I have been seeing several articles on this change. It does not impact those already on social security or singles. It is closing down a so-called loophole that some couples could use whereby one could claim a spousal SS benefit but continue to let his/her own benefit grow to the maximum age 70 benefit---even when the spouse was not yet drawing SS benefits. Couples age 62 and older are grandfathered in to continue to be eligible for this method, but those under age 62 won't get the opportunity. the SS system is seriously underfunded so I for one don't really think this is an unreasonable change to make. Deeper cuts will unfortunately likely be needed too.
And OnebyOne, you are right---SS was originally designed to cover only 1/3 of retirement needs, the rest was to be fulfilled from personal savings and pensions.