I'm not sure this is the reason. 29. Rb4 is not forced in this line. The white rook also has b7 at its disposal.

I think the reason Aronian does not take on c5 on move 28 is that it doesn't win a pawn, since black can win the c3 pawn by taking control of the c-file.

I'm not sure this is the reason. 29. Rb4 is not forced in this line. The white rook also has b7 at its disposal.>

29.Rb7 allows 29...Bxc3, or even better 29...Rac8 30.Rxc8 Rxc8 followed by 31...Rxc3 after the bishop moves (or 31.Rb4 Bd7 32.Be1 a5), when the a7 pawn is indirectly protected by the Bd4+ threat.

<I think the reason Aronian does not take on c5 on move 28 is that it doesn't win a pawn, since black can win the c3 pawn by taking control of the c-file. 28 Rxc5 Rfc8 29 Rxc8 Rxc8 and now 30 Rb4 a5 would force the rook away from the bishop's defense so white must instead move the bishop on move 30 and black wins back the pawn.>

Fine says that every exchange of pieces takes the game closer to an endgame which favours Black's queen side pawn majority.

Recent games have indicated however a problem with this.

In the ending Black has indeed a queen side pawn majority. but White has more space.

White's advantage in space may result in White's king gaining a considerable lead in development over Black's king. In fact White may end up playing with an extra king.

Honestly Aronian's choice looks more dangerous for black to me as black dark squares bishop looks awfully misplaced. The usual opinion about Aronian being unprepared seems rather faulty cliche given the well prepared opening he played here.

17. Qf6

[here alternative is 17. Qd6 which violates positional priciple but seems a more peaceful choice for black: 18. Bc4 Rfb8, 19. Rb3 Re8, 20. Qh6 Qe5 and black will be defending his position for some time to come]

18. Rf3

[this move has been on books since 1992]

18.... Qe5

[18. ...Qd6!? is again more peaceful alternative]

19. ... Bc8?!

[my analysis shows that 19. ...Qe4 leads to a draw by perpetual or equal ending but it optically looks as if white is going to have strong advantage in the endgame. This is what MVL probably feared.]

20. ...Bc7?!

[all of this is played in 2000 in the game Flumbort-Amrein won by Flumbort. This game is not in this database.]

21. Qh6!

[This is Aronian's improvement and now black is in serious trouble as there is no escaping from difficult ending. Flumbort played 21. Qf4 and won the game as well.]

26. ...Be5

[here Aronian conceived nice combination 26....Be7, 27. Rxg6+! hxg6, 28. Bxe7 Re8, 29. Bxc5 with serious advantage for white.]

28. ...Rfb8?

[MVL loses the thread of the game in difficult defence and makes a decisive error.]

29. Rxb8?

[this throws away the winning game. After 29. d6! with threat Bd5 black loses a-pawn anyway in a hopeless position, for example: 29. d6! Rxb3, 30. axb3 Kf8, 31. Bd5 Rc6, 32. Rxa7 Ke8, 33. Bb7 Rb8, 34. Bc6! Bxc6, 35. Re7 Kf8 36. Rxe5 Rxb3, 37. Re7 and black is lost.]

33. Be7?!
[there is hardly anything better but this is not a move that can be considered good.]

33. ...Kg7?!

[what an awful waste of tempo in a position where every tempo counts. 33. ...f6! equalizes instantly as king approaches passer through f7 without any fear.]

34. ...Rd4??

[this is clearly a blunder as there is no stopping pawn now without a loss of material. 34. ...Re4! and the pawn is stopped since 35. d7 Rxe7, 36. d8Q Rxa7 and white cannot do absolutely anything.]

36. ...c4

[last attempt on tactical tricks]

37. g3!

[precise execution. Promotion would be a grave blunder: 37. d8Q?? Rxd8, 38. Bxd8 Bd4+ and draw.]

37. ...Rd2+

[of course 37. ...Bd4 loses to 38. Ke2]

=================

This game goes to show how little is played nowadays. 20 moves is just the theory and the rest of the game is with quite a few errors in 14 moves when the game is decided. Another 8 moves in hopeless position and the game is over.