The longer I live, and especially after having read that post, the more I think the civil institution of marriage is a mistake. We would be better off, if it remained a purely religious or traditional ceremony, without the government putting a stack of papers into the equation. Just let people be happy together; even bound by a promise, if they wish so, but without the external pressure and the fallout in case they f…
What if you end up in the hospital, unconscious? Who makes care decisions for you? Sure, we can have a legal framework just for that, but that's just one more thing you have to do. What if you die? Who gets your stuff? Sure, you should have written up a will, but many people haven't done it. More overhead.
Something to consider is how long homosexual communities have fought for marriage equality. Yes, part of it is certainly symbolic, but I've spoken to gay/lesbian friends who (when they couldn't get married) were anxious all the time about not having the legal benefits around marriage.
I think it'd be possible to not have legal marriage anymore, but you'd still have to have a bunch of legal constructs around the idea of being partnered to someone in order for many life things to work properly. Whether or not that would be better or worse is certainly up for debate.