I have found some information about when and why Graceland was open to the public makes an interesting read:
At Elvis's death, the estate he left was not at all broke, however, there was a cash flow problem, especially with the upkeep of Graceland that cost Lisa Marie over half a million dollars a year. Due to this fact, it seemed only logical for Priscilla and the executors of the estate to open Graceland to the public as it was slowly depleting Lisa Marie’s inheritance to pay the taxes and upkeep on the property.
Priscilla Presley hired Jack Soden, a Missouri investment counselor at the time, to plan and execute the opening of Graceland to the public and oversee the total operation. Graceland opened for tours on June 7, 1982.
Over the next few years the properties in and around Graceland were acquired. Today all the shops and attractions in what is now known as Graceland Plaza are owned and operated by the Elvis Presley Enterprise (EPE). Some of the property near Graceland was already owned by the Elvis Presley Enterprise. It was purchased in 1962 but had never been developed.
A very important development for the Graceland visitor experience was the addition of Elvis’s Lisa Marie jet and Hound Dog II Jet Star planes. Vernon Presley, Elvis’s father, had sold these two planes in the year of 1978. The current owners of Elvis Presley Enterprise brought them back home to Memphis in a joint venture and opened them up for on-board tours in 1984. Another major tourist attraction development was the opening of the Elvis Presley Automobile Museum in Graceland Plaza in 1989.
The Graceland Mansion has continued to grow and develop into a very profitable tourist site. In the latter half of the 1980’s, Graceland Crossing, which is a neighboring shopping center with stores that featured Elvis-related items, was built. Graceland Crossing is situated just north of Graceland Plaza. It was independently owned until Graceland purchased it in the fall of 1997 as an addition to Graceland Mansion visitor amenities.
Following this purchase was another major development that involved a purchase of an existing nearby hotel property. The property was renovated and renamed “Elvis Presley’s Heartbreak Hotel” in the year of 1999. There is ongoing and continued expansion and enhancement of Graceland Mansion visitor facilities. The developments of new Elvis exhibition projects are planned for the Graceland complex as well, and since opening Graceland to the public in 1982, it has hosted millions of visitors from every state in the union and nearly every country of the world.
The opening of Graceland Mansion has also benefited the tourism trade in Memphis in general. Before its opening, there was only minimal tourism trade in Memphis, Tennessee. Graceland Mansion quickly became the cornerstone of the tourism industry in Memphis and the surrounding region.