Was the Fall of Rome Inevitable?

After the end of Pax Romana, the fall of Rome was almost obvious. The first reason was it's geography. It had the shape of a doughnut and the boarders were hard to defend from barbarians. Also, the army enlarged but it wasn't as powerful and organized as it used to be. The government grew as well, to a point of being to big to control. In addition to this growth of population, the economy declined drastically but the luxury import wasn't stopped although the economy wasn't strong enough to support it. The death of slaves was increased, therefore more people had to start working. They lacked technology too. It was clear Rome will fall, nothing lasts forever. It was unfair to blame it on religion tough; what they needed was a strong emperor.