Ummah (a Nation) was created when Prophet Muhammad migrated to Medina and created a society which was egalitarian, with more or less similar socio-economical standing, irrespective of religious views and origin. This egalitarian society lasted for a few years after Muhammad's death during the reign of of Rashidun.
Later on, the whole Arab was Islamicized and the newly converted Muslims spilled out of Arabia. There is a controversy whether the first step out of Arabia was more religious/political in nature or economical? In few years, the new-converts occupied large areas of Northern Africa (the Maghreb) and present day Iraq snatching it from the Sassanid Empire. In few years, they created an empire starting off with Umayyads (662 - 750 AD) followed by Abbassids.
Let's go in history for a while, we know that first ever Akkadian Empire was based in Mesopotamia, followed by Babylonian, Assyrian and later Parthians, Macedonian, Sassanid and then 4 Muslim Empires (Rashiduns, Umayyads, and Ottomans) and these societies were more hierarchal in nature than the preceding empires. Compare these with areas where agriculture was not the prime mode of sustenance for eg. Central Subsaharan Africa or even Arabia at that time. emerged in areas bordering water, which could sustain agriculture, for eg. Euphrates/Tigris in present day Iraq (Mesopotamia), The Nile in Egypt, Yellow River in China etc. The first ever
Arabian Peninsula, as we know is a desert, the prime mode of sustenance before the oil emerged, was trade and by lodging of pilgrims during the busy Hajj season. Hajj is an yearly event where people come to pray at Ka'aba. Notice, this tradition is pre-islamic. People have been coming for Hajj since the time of Abraham, the forefather of all three monotheistic religions. During the peak Hajj season, people used to do trade all around the peninsula and finally would come to Mecca for trading goods, as it was a big market. But there was another source of income in Arabia, namely 'Ghazu'. Ghazu is an arabic term meaning 'raid' in which pre-islamic tribes used to attack the enemy tribes returning back from the bordering Sassanid and Roman empires after trading goods. In Islamic history, the 'War of Badr' started in the similar manner when Muslims Mediniites attacked the Meccan Pagan tribes returning from Syria, who in return attacked Medina with 1000 soldiers, and were defeated by 313 Mediniites. When the Arab became unified under Islam and thus created an Ummah, this concept of 'Ghazu' was inapplicable within the Arabic territory since no enemies existed anymore in Ummah and so Arabs spilled out. Notice, agriculture was never the source here.
Also, whenever the financial capital is limited, societies remain egalitarian. Lets go back in time again. In hunter-gatherer societies (pre-12,000 BC), availability of food depended upon the big-game or edible plants. If you can find animals that you can kill or plants that are edible, you can survive otherwise you die. As a result families were smaller because either you can't afford or you cannot feed them and they're always on foot to look for the source. Agrarian societies changed that option - with agriculture, you had a huge financial capital that you can secure and sustain, which not only settled the people but spiraled the Agricultural Revolution that led to the formation of civilization. But agrarian societies did not develop everywhere for e.g. Arabia, as it depends on water sources. Arabia remained a non-agrarian society with limited income and hence remained more or less egalitarian, plus with a new religion which promoted equality in all sense.
When these Arabs spilled out and conquered the agrarian societies of Sassinid and Roman Empires, they adopted the same heirarchial system which was primogenial (son after father) in continuity under the wrap of Caliphate. The Prophet and early Caliphs of Rashidun were called by their given names; they were approachable and led a simpler life. However, in hierarchical societies and empires, kings have always been considered 'Son of God,' 'Avatars' or even 'Gods', prevalent in mythologies. Since 'Son of God' was not an option in Islam, it was replaced by words like 'Shadow of God on Earth' or 'Zull-e-Ilaahi", where the so-called Caliphs stood outside the public arena and were unapproachable. Courtiers used to kiss the ground in order to come to their courts, executioners stood beside them symbolizing that life and death remained in their hands.
This was an ultimate break, one from the completely egalitarian society to a high complex hierarchical society, one which was based on simple trade to the empire based on agriculture. In order to maintain that empire, they had to be expanded by attacking other agrarian societies, a hallmark of every highly complex hierarchal agrarian society.
This was also a break from an ideal concept of Ummah that was initially created. Over the centuries, different movements sprouted in the Islamic societies attempting to restore the original concept of Ummah. A lot of different interpretations of Islam rose up, some dwelled into the concept of mysticism, reminiscing the time when the Prophet used to quietly meditate in the Caves of Hira (Mecca); others reacted with an open revolt against authorities; philosophical system arose, a lot of them inspired by earlier Greek philosophies thinking the Greek rationality was the way Prophet suggested, others believed in literal interpretation of the . All were the means to re-create Ummah, which was lost after the move to a comparatively modern way of living.
Among the different movements in the masses, the Islamic system that continues is based more or less upon literal interpretation of Scriptures that continues to this day. In different parts of the Islamic world at different times, in this paradigm, different movements arose in order to re-create similar Ummah that Prophet Muhammad once created in Medina. So far, they have not been successful.
Currently, the trend continues - modernity is always associated with fundamentalism, more advanced societies tend to be more modern, agrarian societies as compared to hunter-gatherer-trading societies in the past, Israelites from the Promised Land to the pagan world of Babylon. as compared to agricultural societies now. Whenever we see new developments in a society that tends to differ from the ideals of religions, fundamentalism grows irrespective of religion. We see the similar trend of increased religiosity in the Muslim Diasporas in the west, who come here for a better life but consider the western way of living a threat to their own, that reverts them back to the very fundamentals of their religion. The increased religiosity in their own land is a mixture of political instability, lack of democracy, opposition to modernity and lack of education. Similar examples could be seen in Judaism when the Babylonian Emperor in 586 BCE expelled the
The question is, is it ideal to go back to the same concept of Ummah that was created 1400 years ago; or we need a different form in this different politico-economico-social environment, one which is more viable with the current world?