Not quite correct picture. The tendency did start during the Revolutionary Wars just because the bulk of the French armies were ill-trained volunteers. By the Napoleonic times the bulk of the foot was line infantry acting in the battalion formations (not forming a single line as in XVIII). When closing with the enemy the battalions would either attack in a column or spread into a linear formation, usually 3 ranks deep. In Prussia and Austria the 3rd rankers were extensivelly used as skirmishers and often were detached from their companies. Until 1807 in Russia all jager regiments were formed on 2 ranks. In October 1813, to compensate for the heavy losses, Napoleon issued an order " ... Emperor orders the entire infantry of the army to form up in 2 ranks instead of 3, in that his Majesty regarded that the fire and the bayonet of the 3rd rank useless." Needless to say that the linear infantry was firing by the salvos.
As for Nappy and the rifles see, for example,
https://en.wikipedia.org/wiki/Napoleonic_weaponry_and_warfare#Firearms I did not find any reference to the rifles being used in his army but would be interested to see a link or quotation confirming what you wrote. However, even within framework of what you are saying, the rifles (if existed) were too few to play any significant role in his warfare. This pattern was not unique:
In Russia between 1803 and 1812 the factories in Toula (Tula) issued 20,000 rifles but in June 1808 the rifle was withdrawn and used only by NCOs and 12 marksmen in each jager company.
In Austria the jägers in the 1st and 2nd rank were armed with short muskets, while those in 3rd rank with rifles. The NCOs also carried rifles.
In Prussia (after reform) the jager battalions (2 or 3 of them) had rifles including the hunting rifles.
BTW, I was asking about Napoleon within the OTL/close to OTL framework, not in a seriously different history but even in OTL he was not fighting the major wars without an interruption so his rejection of the rifles was not done out of a desperation.