Oh sure, they'll probably leave him in his current state for a while, possibly for a few years, but I doubt 616 Logan/Wolverine will never be back.
Yeah, Old Man Logan isn't as popular as Wolverine, and he's definitely not a replacement. Normal, 616 Wolverine will be back. Just like Thor will take his name and hammer back, Steve rogers will regain his youth and take back his shield, etc.
Except current Logan wasn't the Wolverine anybody wants to read anymore. He's a tame school teacher who lost all of his edge.
Old Man Logan is the Wolverine people would rather read.
Your examples are a bit off as well. Steve Rogers isn't Captain America now, but he will be. Thor doesn't have the hammer, but he will.
Old man Logan is still Logan. He has his claws and his healing factor and he's still Wolverine. They have the character people want to see again. As opposed to the bore he became in the team books of late.
Or are we still waiting for Mar-Vell to return as well?