Allah has only created one religion and only one.
ان الدین عند الله الاسلام
We have the same God, we are the same humans, we have the same wisdom which tells us love is good, jealousy is bad, arrogance is bad, sacrifice is good.
What you see as changes are only small tiny changes in commandments + deviations of previous religions.
The verses presented in this narration points out that there other nations but only one religion known as Islam.
See Pg. 413 & Pg. 414 & Pg. 415
But why do we need prophets again and again and again?
- To correct the deviations. Prophets have been killed, their sons have been killed, their successors have been killed, their followers have been killed and tyrants ruled again. If you study history every prophet has a nation in which he is struggling to guide them, usually those people are misguided by a tyrant king like Nimrod, Pharaoh, etc.
- To constantly admonish humans. See this narration from Nahj al-Balaqa:
Then Allah sent His Messengers and series of His prophets towards them to get them to fulfill the pledges of His creation, to recall to them His bounties, to exhort them by preaching, to unveil before them the hidden virtues of wisdom and show them the signs of His Omnipotence namely the sky which is raised over them, the earth that is placed beneath them, means of living that sustain them, deaths that make them die, ailments that turn them old and incidents that successively betake them.
بَعَثَ فِيهمْ رُسُلَهُ، وَوَاتَرَ إِلَيْهِمْ أَنْبِياءَهُ، لِيَسْتَأْدُوهُمْ مِيثَاقَ فِطْرَتِهِ، وَيُذَكِّرُوهُمْ مَنْسِيَّ نِعْمَتِهِ، وَيَحْتَجُّوا عَلَيْهِمْ بَالتَّبْلِيغِ، وَيُثِيرُوا لَهُمْ دَفَائِنَ الْعُقُولِ، وَيُرُوهُمْ آيَاتِ الْمَقْدِرَةِ: مِنْ سَقْف فَوْقَهُمْ مَرْفُوع، وَمِهَاد تَحْتَهُمْ مَوْضُوع، وَمَعَايِشَ تُحْيِيهِمْ، وَآجَال تُفْنِيهمْ، وَأَوْصَاب تُهْرِمُهُمْ، وَأَحْدَاث تَتَابَعُ عَلَيْهِمْ
How many times do we need to be reminded to do good? To remember death? Remember judgement day? For the same reasons we need to admonishers...