Invalidating hundreds of thousands of 4-year-old marriages, some of which are elderly husbands or elderly wives at the very end of their lives, would have a backlash so fierce it would probably require the passage of a Marriage Equality Act that enshrines Obergefell into federal law.
Couldn't the existing marriages be grandfathered in, and states be then permitted to ban future marriages only?
Well, yes. With Judicial Activism, anything's possible.
Obergefell was political activism by the SCOTUS. It redefined the term marriage
sub silentio. So why couldn't they do creative sculpting in crafting a new opinion?
Obergefell, like
Roe, was Judicial Activism at its worst. That being said, reversing
Roe would not create a legal and bureaucratic nightmare.
Obergefell, on the other hand, would indeed be a legal and administrative nightmare. As a moral issue, I obviously do not support
Obergefell, but I do view it as a
fait accompli and while I don't sign off on SSM, it's one of those things that's "on them", morally. I do see a situation where a repeal, even a partial one, would do nothing but make lawyers rich.