By the early 1980s, Atari's reign of dominance quickly began to yield as new competition entered the video game market. With the introduction of Mattel's Intellivsion (1979), the Atari 2600's technology began to look obsolete and a nearly knockout blow came in 1982 with the release of the vastly superior ColecoVision.
Atari already figured that the 2600 was going to become obsolete roughly around 1980 and in 1979 began to design a new system. Preliminary work on the successor, named at the time the Atari Video System X - Advanced Video Computer System, began and was based off of Atari's growing line of home computers, the Atari 400 and 800. The name was changed to the Atari 5200, though there are a few known copies of the Video System X that do exist.
In 1982, the Atari 5200 was released with 4 controller ports on it, whereas the vast majority of systems at the time had only 2. In 1983, the system was re-released with only 2 ports and was reconfigured so that Atari could release an Atari 2600 adapter allowing backwards compatibility.
Sadly, the 5200, albeit a much improved system, was doomed basically from the start. In 1983, Atari made massive blunders and a glut of terrible video game titles led to the video game market crash of 1983. At the time, video games were viewed as a passing fad and Atari discontinued production of the 5200 quietly in 1984.
A little over half of the games for the system sell for under $10, but a surprising percentage are starting to gain value due to the somewhat limited production of them and are going for $10 - $50 with one title regularly fetching over $100.
