Yes, I became aware that they had abandoned the "born that way" argument years ago. It's now, "So what?" You can do whatever you want.
I argued at the time that
Obergefell v. Hodges would create huge problems for the future. IMO, the Court did not think its way fully through what they were doing. My position was always that they should just stay out it, gay marriage was a question for the states solely, under the Constitution.
Effectively it was up to the people, acting through their representatives, to set the terms of marriage. As has always been the case, the burden was firmly placed upon the proponents of change (here, the proponents of gay marriage) to persuade enough of their fellow citizens to make that change in their local laws. This is how democracies work. It is the very nature of our form of democracy. Yes, it moves slowly, too slowly sometimes, but it still works. And it works better than anything any other peoples in the history of humanity have ever been able to come up with. But some people are just not willing to put in the time to do things the right way.
And some of those impatient people work on the Supreme Court. So the Court made a mistake. Incapable of resisting the emotional impulse to show those poor red state slobs up, they substituted their judgement for the will of the people. IMHLO, they were acting outside their delineated powers. The Supreme Court itself acted unconstitutionally in that case. Unfortunately, there exists today no
reasonable mechanism for us to fix it when they screw up like this (see
Marbury v. Madison (1803))
More practically, what does this mean for the future? This part finally gets to what you wrote. If the people, acting through their democratically elected representatives, cannot set the terms of marriage, then they cannot prevent any other type of marriage either. Think about it. The people can no longer say siblings cannot marry. Nor any other family members. Nor can the people even limit marriage to "between humans." Who can now stop someone from marrying their pet? Their computer or cell phone? Their dead friend or relative? A tree? A sex doll? A Johnny Maziel poster? Whatever you can think of, someone in the future will marry it because of the shortsightedness and impatience of the liberal wing of the SCOTUS. They opened a type of Pandora's Box on marriage.
Here is my example of an extreme result from all of this that we will see in our lifetimes. Someone will make a clone of him or herself. Then he/she/it will marry the clone of he/she/it. Who can stop it now? Then he/she/it will pass all of his/her/its assets to the clone. With all tax and other legal implications neatly accounted for. And then repeated into perpetuity. I actually wrote this script about 10 years ago. Never sold.