How come the Airbus A- 320 is such a popular aircraft?

With the Backlog order of more than 3000 aircraft's it brings on a question to Airbus as to how they are preparing to fulfill the requirements of customers on the time?

Airbus A- 320 is a narrow aisle bodied aircraft with the seating capacity of up to 200 passengers the aircraft's is popular among the likes of regional carriers of the country and is also considered to be an alternative for the Boeing 737 series.

There are approximately 200+ service companies in this world who help the customers reach their destination.Most of them don't have enough capital to infuse into wide bodied aircraft's so they choose smaller airplanes for their services. Also the demand in their region might actually be less, so getting a wide bodied aircraft isn't a viable option.

Aircrafts like the A 320 can bring in more income per seat than the wider aircraft's, also it saves a lot of money on the fuel.