You have given the parallel similarities between zurashtrian rituals and Muslim Namaz. Islam never claimed to be invented at the footsteps of Mecca by Prophet Muhammad PBH. Quran says as that, this is an extension of original "Deen" which was given to mankind for their own welfare and salvation۔
The previous religions became obsolete when people molested their faith with paganism and lost track of the original message.
Quran mentions that every race and community was warned by a messenger of Allah. We don’t know what was the status of Zoroaster, who knows ? may be he was preaching the same message to his people as prophet Abraham did and other prophets did.
What difference does it makes who was practicing 5 time prayers before Muslims came around. It is not important how it was started but it’s important to maintain as it was ordered by Allah.
Please read Quran:
Quote: 10th Para .Repentance IX sorah Tauba 9 chapter 18
“The Mosque of Allah shall be visited and maintained by such as believe in Allah and the Last Day, establish regular prayers and Pay Zakat. And fear none (at all) except Allah it is who are expected to be on true guidance.”