Allah is the Lord, Master, Creator, Sustainer and Developer of all the worlds.
Both the physical and the spiritual world.
After creating things, God leads them progressively to higher stages of development.
No people are ever deprived of God’s physical and spiritual blessings.
If any revelation was meant only for a particular people (as was the case before Islam), separate revelations were sent to other people. This was necessary because humans were widely dispersed in the world and easy means of communication between them did not exist. That is why so many prophets were sent.
With the coming of Islam, humanity had advanced to the point where one revelation was sufficient for entire mankind, and for all time.