I disagree, I don't think we will see it in our lifetime, but two or three generations ahead, certainly. If the world has managed to save itself from obliteration that is. Look at the leaps made since just the 50's! Hell at the rate of straight guys having gay sex.. there may not even be Gay/Straight by then. The lines have become quite blurred not just in gay porn, but in private society. You would be amazed at what a woman will live with to hold onto her man. Funny though - not so much the other way around huh.
As far as the rest of the world - well I hardly think they are really waiting on "Western Values". Europe has been decades ahead of America where sexual freedoms are concerned. There are still those nations who's religious zealot regimes will fight to the bitter end, but even they will eventually fall. It isn't just "Gay Rights", it is evolution. Think about it, perhaps if more married men were off fucking their buddies on the weekends the divorce rate would probably tumble for the first time since the 60's.
The only thing that will stall it (not stop it) is apathy. People becoming complacent because they became too comfortable, THAT my friends is why we have "President Trump". That's right, people got fucking lazy and the knuckle draggers managed to vote a glorified game show host into office. If he is still there after this next election we all need to hang our heads. THAT was totally avoidable, but nobody ever really believed it would happen. We have become a people so caught up in our day to day "Social Mugging" that we have allowed a bunch of "C" team misfits take over our affairs.
It's true, there was a time the world used to look to us, that time has come and gone. Yes, I think one day there will be global human rights that include same sex marriage. But nothing good ever came without a price.