The division of the day into 24 hours has its roots in ancient civilizations and is not necessarily tied to a base 10 system. The concept of dividing the day and night into equal parts has been observed and practiced by various cultures throughout history, albeit with different approaches.
The ancient Egyptians are often credited with introducing the 24-hour day around 2000 BCE, dividing it into 12 hours of daylight and 12 hours of darkness. The Babylonians, Greeks, and Romans also had similar systems. These divisions were primarily based on astronomical observations, such as the movement of the sun and the stars.
The choice of 24 hours was likely influenced by the convenience of dividing the day into manageable parts. The number 12 has many divisors (1, 2, 3, 4, 6), making it relatively easy to divide both the day and night into equal segments. The adoption and standardization of this system happened gradually over centuries, as different civilizations interacted and shared their knowledge.
As for why the world has largely agreed to this system, it can be attributed to the historical influence of the cultures that developed and popularized the 24-hour day. The widespread use of this time division in various fields, such as astronomy, navigation, and international communication, has contributed to its continued acceptance and adoption.
It's important to note that the base 10 system you mentioned is related to our numerical representation and not necessarily tied to the division of time. The choice of a base 10 numbering system is arbitrary and influenced by factors such as the number of fingers we have, which made counting in groups of 10 convenient.
While alternative proposals for timekeeping have been suggested over the years, such as decimal time, they have not gained widespread adoption. The existing system of 24 hours with 60 minutes per hour and 60 seconds per minute has become deeply ingrained in our daily lives, making it challenging to introduce significant changes without global consensus and practical necessity.