I am disagreeing about the non committment of the Guard at Borodino - Napoléon had good reasons not to commit it.
At Borodino the campaign was already lost regardless of the tactcial victory of Napoléon and his Allies.
Napléons loss of touch with reality and the unability to listen to trusted subordinates did cause the most havoc and let to total distruction of the allied Grand Armée.