Tell you what I can see happening:
1) The inevitable Moz/Marr reunion gig(s), with or without Rourke and Joyce.
2) Just as is the trend, touring classic albums. I went to see Adam Ant doing Dirk Wears White Sox, now he's touring Kings Of The Wild Frontier. People want to see this stuff. Regardless of how many times you are told that the last album was the best, if there's money in it, and the fans will pay, it will happen.
You are hedging your bets quite a bit here. If you would count a Morrissey/Marr "reunion gig" as them both being on the same stage at some point and performing any piece of music, Smiths or not, with any configuration of "lawnmower parts" playing alongside, it is just barely possible that they might do this for some cause or when receiving some award. But they are never going to perform a complete show where they are the headliners, and they especially are not going to call anything The Smiths, and they are absolutely never going to tour The Queen Is Dead, or whatever album.
There is money in it and it would sell tickets. People do want to see it. That last bit is exactly why it won't happen. First of all, Morrissey would rather make you want something you can't ever have than give it to you. Second, I think that Johnny Marr is proud of his work with The Smiths, and just as equally embarrassed of his association with Morrissey. I believe that when he chats with his peers, such as Bernard Sumner, they laugh at Morrissey. They've all become mature adults more or less, and Morrissey's whole act is looked at as something that a certain type of person embraces, but that is actually a huge joke. Watch Marr singing "Getting Away With It" the Electronic song about Morrissey.
On the other hand seeing Marr play all those Smiths songs does make me want to hear Morrissey, or almost anyone else, sing them, and it would probably be an enjoyable show. It would overshadow both of their careers and make everything they've done since 1987 or so seem irrelevant.
Morrissey doesn't need the money. He can keep releasing the same songs in new formats forever. He would have to be truly broke and living on the street, or have a heroin habit, or something very drastic. Johnny Marr left him and maybe those rumors are true that he once wanted to reform, but he was in a much better position then. He would have been able to negotiate terms that would suit his ego, and it wouldn't have been looked at not as a reunion so much as poor lost Johnny Marr going from backup gig to backup gig finally realizes he needs Morrisey and the brand name The Smiths to be relevant. That, Morrissey would have done just maybe. But now? Johnny Marr rescues Morrissey from obscurity just like he did in the very beginning of the band? That's how what's left of the NME and everyone else who has knives out for Morrissey would frame it. They are never, ever going to get back together again.