That could happen. I hope it does.
Not a chance.
You need both Ronaldo and Messi to retire or there will be no other winners.
OK this is what I think would need to happen for him to stand a chance.
KDB gets a big MOTM against France with goal(s) and does the same in the final, scoring the winning goal in the final. That would get him the golden ball.
Then he'd need to have a record breaking start to the season with us. Ozil got 19 assists in the first half of the season in 14/15 - Kev would need to be putting up those kind of numbers maybe breaking the assist record of 20 before Christmas and add ~15 goals, to the point where he's being already crowned POTY definitively. No discussion, no Salah etc. just definitive.
Add some MOTM performances in the big Champions League games when everyone is watching.
As a team we'd need to be doing similar things to last season, breaking winning streak records, posting obscene goal numbers, surging to a double figure lead in the league and having some big wins in the top 6 games.
While all of that is happening, Ronaldo would need to have a slow start at Juventus, to the point where like this season he only had a handful of goals by the voting in December and Messi needs to not be at his best.
If all of that happened, he'd have a good chance.