You failed to address the Ayaat that clearly called those who disobey Muhammad as "disbelievers". Your view contradict the Qur'an outright. The Qur'an is the Muslim's reference.To say that as of now, only Prophet Muhammad's external Shariat is valid is egoistic. This is what I am referring to. To a Hindu, I say become a true Hindu and that will be automatically Islam (regardless of non-usage of His term Islam), to a Christian, become a true Christian and that will automatically Islam and so on.
This is the view of the Qur'an...if it's egoistic let it be...If someone says all other theologies are incorrect, all other Jurisprudences are incorrect and the one followed by Prophet Muhammad(pbuh) is the only valid one today, then I will say this is being egoistic.
64. And We did not send any messenger except to be obeyed by permission of Allāh. And if, when they wronged themselves, they had come to you, [O Muúammad], and asked forgiveness of Allāh and the Messenger had asked forgiveness for them, they would have found Allāh Accepting of repentance and Merciful.
An-Nisa'
32. Say, "Obey Allāh and the Messenger." But if they turn away then indeed, Allāh does not like the disbelievers.
ِAl-Baqarah
65. But no, by your Lord, they will not [truly] believe until they make you, [O Muúammad], judge concerning that over which they dispute among themselves and then find within themselves no discomfort from what you have judged and submit in [full, willing] submission.
19. O People of the Scripture, there has come to you Our Messenger to make clear to you [the religion] after a period [of suspension] of messengers, lest you say, "There came not to us any bringer of good tidings or a warner." But there has come to you a bringer of good tidings and a warner. And Allāh is over all things competent.
Al-Ma'idah
Nothing to add after these Ayaat.