It’s probably too late for Smoker and Tashigi to make a comeback. I think Oda gave up on them after Punk Hazard. Even if he did come back the power up would have to be ridiculous for him to remain relevant. Smoker is not young like Koby so his potential was never going to be that high to begin with.
Learn to read brother.
Kuzan saved Smoker at the end of Punk Hazard.
Kuzan doesn't have a role in the story or appear again (only gets two brief mentions) until the arc we just finished.
Smoker gets mentioned and shown at the end of the arc after Dressrosa, reflecting on what occured/what he partially influenced in it, getting sent to THE PLACE that's the subject of the arc that just ended to see a specific person.
Koby, my favorite marine since chapter two, who I was praying to join the main story, gets jackshit until this arc that just ended, except for maybe just under 19 pages of content (max) to establish his existence and where he'll be when he finally gets a story.
In between the end of PH and the current part of the story, both Smoker and Koby in two separate OP movies overseen by Oda had large roles consistent with their portrayal in series, and in Smoker's case alongside other major players in the series; once again, Oda approved and in line with the story itself.
Where did we last see Smoker? We saw Tashigi and the PH kids in the last arc, and we saw Smoker at the very end of the last arc (aside from a single flashback panel) riding his devil fruit powered motorcycle across the ocean, dragging a mysterious box behind him, traveling to where Koby and Tashigi are to be informed about everything that's happened in that arc, which includes the actions of Kuzan.
The above scene is also known as aura farming, ad
Why would Smoker appear in the main story again before:
The other main marine Koby reappears for a substantial role
-The place he's traveling to is finally put in the story meaning he doesn't spoil anything
-Any Marines aside from two others in the Yonko saga appear for significant roles as they're on the back burner as a faction
-His friend as established when Kuzan first mentions Garp and Smoker on Long Ring Long Land, when Smoker and Kuzan share their final pre-timeskip scene together, and Kuzan comes back to save his life and foreshadow Smoker's future with a clear line of dialogue that earlier in the same arc was told to Smoker by another character
You can't answer any of these in a way that isn't total deflection or totally illogical.