Sure, but is it wiser to do so?
Practically, suppose, Allah did not give a new Book called Quran, but kept it as Bible, with corrections. If Allah did not change the Prayer, Qibla, and other Ordinances, then how can be said, these are new People? How could have the new People, be known from the People of the past? And practically how one can say, they are any different?
Perhaps, the guidance was lost among the children of Isreal.
From Musa (a) up to Isa (a) (not inclusive of the latter), the rituals require an presence of a leader appointed by God. It's just too ugly if not. Isa (a) mainly abrogated stuff in that regard.
The temple and it's rituals for repentance are just too ugly if without presence of a leader appointed by God. Otherwise better to repent in private then in public. Scholars and clergy can't play these roles without presence of a leader appointed by God.
It's beautiful but only with the leaders of God leading it. Mainly, after Musa (a) with Haroun (a), then Samuel (a), then Talut (a), then Dawood (a), then Sulaiman (a), etc...
Simon (a) as honorable that soul is, is not the same.
In this case, if he wished to, he should not make Quran the final book but provide Surahs to Imam Ali (a) all the way to the Mahdi (a), and make Quran more explicit in appointing Ahlulbayt (a) in a way no one can be obtuse and deny no matter how much they tried.
The reason is because Islam is designed in a way, that allows people to deny Ahlulbayt (a) but work with the Shariah and if they fear God, will be lead to Ahlulbayt (a) and see them in the Quran.
A lot of it's design is mainly about seeing Ahlulbayt (a) in Quran but without over explicit in appointing them nor silent regarding them, for example, blessing the family of Mohammad (s) in Salah and comparing them to the family of Ibrahim (a).
A lot of it is understanding universal design of the religion and understanding the creed of Ibrahim (a) with Mohammad (s) including that of Imams after him.
And the reason why Quran takes a middle ground between explicit and hidden is to allow people to be obtuse regarding it similar in the way Yaqoub (a) gave his sons an excuse to come to Islam after attempting to kill Yusuf (a). He knew they would lie, they were lying but gave them a way to stay in the religion from the outskirts till they repented. The advantage is that the Quran stays intact.
But in making this way, and because he wishes for religion to say high, he decided to not make the successors of Nabi Mohammad (s) receive scriptures that would add to the Quran. This way the focus is on interpretation but designed the Quran in abnormal way that his friends have access to while his enemies are denied access too.
If he made it that they receive scripture, people would have rejected theirs and then Quran would not have the prestige it has now.
This way, the final umma is not replaced and in no need of replacement. This is why Imam Ali (a) continued and said:
Allah the Glorified, has distinguished you with Islam and has chosen you for it. This is because it is the name of safety and the collection of honour. Allah the Glorified, chose its way and disclosed its pleas through open knowledge and secret maxims. Its (Qur'an) wonders are not exhausted and its delicacies do not end. It contains blossoming bounties and lamps for darkness. (The doors of) virtues cannot be opened save with its keys, nor can gloom be dispelled save with its lamps. Allah has protected its inaccessible points (from enemies) and allowed grazing (to its followers) in its pastures. It contains cover (from the ailment of misguidance) for the seeker of cure and full support for the seeker of support.
So, the Sermon you quoted, talks about replacing a people with another people. قوم with another قوم.
This "Change of People" was done, by sending a new Prophet to the Arabs to reveal for them a New Holy Book, with new Set of Laws and Ordinances, and choosing them as the best Ummah.
Now, having said that, consider one of the strongest Laws of Torah, known as Sabath, which Quran confirms it:
"... We said to them, "Do not transgress on the sabbath", and
We took from them a solemn covenant." Quran 4:154
" لَا تَعۡدُوا۟ فِی ٱلسَّبۡتِ وَأَخَذۡنَا مِنۡهُم
مِّیثَـٰقًا غَلِیظࣰا"
This was such a Strong covenant. As Torah also says:
"The Israelites are to observe the Sabbath, celebrating it for the generations to come as a
lasting covenant." Exodus 31:16
"Observe the Sabbath, because it is holy to you.
Anyone who desecrates it is to be put to death; those who do any work on that day must be cut off from their people."
It was supposed to be a lasting covenant.
Now, consider this covenant that was so, strong, that was to be an everlasting covenant and whoever broke it, was to be put to death, was abrogated, once Jesus had come, let alone when Muhammad came.
Now, why do I say these? consider What God says in Quran:
وَإِن تَتَوَلَّوۡا۟ یَسۡتَبۡدِلۡ قَوۡمًا غَیۡرَكُمۡ ثُمَّ لَا یَكُونُوۤا۟ أَمۡثَـٰلَكُم
"....And if you turn away, He will replace you with another people; then they will not be the likes of you." 47:38
"O ye who believe! whoso is turned away from his religion - God will bring (instead) a people whom He loves and who love Him, lowly to believers, lofty to unbelievers, strenuous in the way of God, fearing not the blame of him who blames. That is God's grace! He gives it unto whom He pleases, for God both comprehends and knows" 5:54
Now, consider, was not the fate of People of Quran, exactly like the fate of Bani-Israel, as Imams had said?
It is obvious that, changing the people of the Quran can happen in the same way as happened to Bani-Israel, meaning, God sends a new Prophet to a different people (Persians), and choose them over Arabs, and gives them a new Book, with new Laws and Ordinances.
Now replacing Arabs with a New people, is very difficult for Arabs to accept.
Now, consider what Imams have said regarding the Qaim:
وعن الباقر ع إذا خرج يقوم بأمر جديد وكتاب جديد
وسنة جديدة وقضاء جديد على العرب شديد
Imam al-Baqir (peace be upon him) said:
"When he (the Mahdi) rises, he will rise with a New Command, a new Book, a new Way of Life, and a new Judgment. It will be severe on the Arabs."