What replaced GMT?

In the realm of timekeeping and international coordination, the question often arises regarding the successor to Greenwich Mean Time, colloquially known as GMT. With the advent of more precise and globally applicable timekeeping systems, GMT has gradually been phased out in favor of Coordinated Universal Time, commonly referred to as UTC. Could you elaborate on the factors that led to this transition, and how UTC has emerged as the new standard for global time synchronization? Furthermore, what are the key differences between GMT and UTC, and how have these changes impacted various industries, such as aviation, telecommunications, and financial services?