I am terribly confused.
The Dome of the Rock inscriptions from 692 talk about Muhammad coming after Jesus. If he was actually not from Mecca as claimed in the hadith and Qur'an, his real origin would still be known and within living memory, especially if he was alive during the conquest of Palestine. The Umayyad claim that Muhammad came from Mecca would be ridiculed.
Why would the Umayyads continue Zubayr's Meccan focus when that legitimized their enemy? They hated the man, had him beheaded and crucified. They also kept Jerusalem as the center for prayer and only later was the qibla switched to Mecca.
It's like the Umayyads were trying to hide the origins of their religion, trying to legitimize it to Christians of the Levant while making it equally attractive to Hijaz Arabs by claiming a Meccan descent. All at the same time.
It makes my head hurt...
692 is 60 years after Mo's death, and 70 years after the alleged 'hijra.' To put that in perspective, Jesus died in 33 AD, and the Gospels were written between the 60s and 80s -- i.e., between 30 and 50 years after his death. Yet we know almost nothing about the life of the historical Jesus, and *literally* nothing about his life prior to its last year, 32-33 AD. The Gospels are chock full of fiction and fallacy. This is true even though Jesus's relatives were still all alive and formed part of the early church in Jerusalem (and Paul reports that he even met with them).
If you go by the *ordinary standards of religious history*, meaning you don't make a special exception for Islam, then the argument that 'people were still alive' imposes almost no constraints on a culture of oral storytelling about a religious founder. Think of how the sirah expands from cryptic references in the earliest accounts, and then 30 years later you have reports which go into exhaustive detail about what happened -- detail unknown to the earlier accounts. It was far worse still in the earliest days following Mo's death. Without clear written contemporaneous documentation that constrains the accounts, nothing gets reported correctly, and fictions proliferate explosively.
As to what the Umayyads thought about Mo, they weren't a cohesive entity, and only with Abd al Malik do we get a picture of what some of them thought -- but only a very dim outline. We don't exactly know what Abd al Malik himself thought, apart from the theology inscribed on the Dome of the Rock and in his coinage. But at that time, in my view, claiming succession to Mohammed as the religious-political quasidivine representative of Allah had become a vital political weapon, and it was at least partially constrained by certain widely prevailing narratives about Mo, as well as to a lesser extent by Qur'anic texts.
But as to why the Umayyads continued the Meccan narrative (to the extent they did -- it's not exactly attested by any contemporary evidence, I think tolerated it would be a better statement), that's easy. You had a Hijazi population that had been indoctrinated in a specific narrative. Al Hajjaj and Abd al Malik, upon crushing the Meccan stronghold, had two choices: One, to try to reverse the prevailing narrative and relocate it in Damascus or Jerusalem or something. Two, to simply accept it, but argue that *Abd al Malik* was the only legitimate successor, unifying all the regions together under the religious movement that he now claimed supreme authority over -- that way you turned this religious fervor in your favor, rather than fighting against it. This is an extremely common, if not default, practice in traditional Middle East conquests. The conqueror rarely obliterated local religious traditions, but rather argued that he was the fulfillment of them.
It would seem that Abd al Malik effectively tried to incorporate all of the major prevailing narratives into a new multipolar sacred geography, centered on Jerusalem, Medina, and Mecca, which was subordinate to his caliphal authority. And this multiplicity is partly why Islam's sacred geography is so confusing and the tradition records a lot of peculiarities and confusions about it. Rather than making it about Jerusalem/Damascus v. Mecca, the entire thing got sucked up into a confusing morass of legend (such as Mohammed's "night journey" to Jerusalem .... people were just making this stuff up).
In reality, we know absolutely nothing about Mo's early years, and what Muslim tradition reports has been shown over and over to be just as fictional and contrived as Christian tradition about Jesus's early life.
Lastly, yes Wikipedia is absolutely awful for Islamic history, but that reflects the fact that Islamic history is still in complete disarray as a discipline. Which is why Karen Armstrong gets cited as a source.
Topic: Islamic Cultures, Islamic Contexts - Essays in Honor of Patricia Crone