Off-topic alert !!
Is it the same Ali that fought Ayesha according to the stories and many lives were lost in the battle ? So, in case of addition to the Qur'an, the best reaction this guy had was to take a vow of nakedness ?
This is actually not off-topic. This is very much relevant to the topic of Khalifa.
It is already established that the Hadith is nothing but idiotic nonsense. So I will go more into the actual historicity of Ali.
The only physical evidence of Ali from the time is in a Syriac manuscript:"When Maximus saw that Rome had accepted the foul mire of his blasphemies, he also went down to Constantinople at the time when Mu'awiya made peace with the emperor Constans, having started a war with Abu Turab, the emir of Hira, at Siffin and defeated him."
Ali is referred to as Abu Turab. His role was the prince of Hira. It seems like the civil war was bad enough that it forced Mu'awiya to make peace with his external enemies. This physical evidence from the era gives a different account than the traditional stories. No mention of Ali or Mu'awiya being cousins to the prophet. Instead, we get the impression that Mu'awiya is fighting a local provincial governor who went out of line.
It is highly unlikely that any of those political leaders who all claimed to be relatives of the prophet were in fact his relatives or even ever saw the prophet.
It seems like anyone who wanted to gain legitimacy was claiming to be a relative of the prophet. This is also the same lie that Khalifa made up to give himself legitimacy when he claimed that he looked like Abraham. This type of lie is part of the Arab psyche. Arab elite use it to this day. The King of Jordan claims to be a descendant of the prophet and so do many Arab elite. There is a whole booming industry of con artists who can trace your family tree back to the prophet if you pay them a few hundred dollars and they will even give you an official certificate that you are one of the Ashraaf (which is the name given to people allegedly descending from the prophet).
The history of the Qur'an is mysterious. Apparently, hadith collectors/recorders/preserves thought of such an event like burning of all Qur'an's to be a very minor event in the history of Islam. Who cares who burnt all that Qur'an, may be ali, or Usman, or Muhammad...just who cares ?
i beg forgiveness for going so much off-topic.
The history of the great reading is not mysterious. It is likely older than we think. From a purely historic point of view, the great reading doesn't mention any of the events of the Arab conquests or the Arab kingdom so we know that it must predate the Arab kingdom.
Islamic Arab history generally starts with the birth of the prophet, which is supposedly 570CE and is said to coincide with the year of Abraha's expidition. However, even this most important starting point of Islamic Arab history is very problematic. We actually have physical evidence of the inscription of Abraha commemorating his expedition and the year of his expedition translates to 552CE. This is 18 years prior to the Islamic Arab history.
Interestingly, a manuscript by Jacob of Edessa records that the kingdom of the Arabs started invading the Roman teritories when Heraclius, king of the Romans, was in his eleventh year. This translates to 620-621CE. So according to the physical evidence from those witnesses, the Arabs had a kingdom and were invading the Romans at the time when, according to traditions, the prophet hasn't even emigrated yet!
So the dates are definitely problematic and we can also see this in Hadiths where many of the narrators are alleged to have lived over 100 years. So the same tendancy to push the birth of the narrators back would result in pushing the time when the prophet lived forward to make them overlap. I would say that the great reading was probably revealed between 10 to 20 years prior to the Islamic Arabic history dating.