The footage is taken from a film in 2006. I don't think that meaning is there. Even if they were having some type of health issues, I doubt we would know, at most probably some type of announcement after a death. Agreed on your first point though.
It's an excerpt from their movie Electroma https://www.imdb.com/title/tt0800022/ . I really don't know if we should look too much in the meaning of the scene.
I don't think Daft Punk are the type of artists to screw over fans by creating "Last Show Evarrrr" and "Final Reunion Tour (It's serious this time)" type shows.
> I would not be at all surprised if you get the chance to see them perform together again.
People seem to be ignoring the meaning within the video. The way he clenches his fist before the explosion. The solitary walk into the sunset.
I would not be at all surprised if one of them was terminally ill.