Short answers, pulled from the story.
Company sales records indicate the Commodore 64 sold approximately 12.5 million units worldwide, though claims of 17, 22, and 30 million have been made. Independent estimates place the figure between 12.5 and 17 million. Based on the 12.5 million figure, the C64 remained the third most popular computing platform into the 21st century until the Raspberry Pi family surpassed it in 2017.
The Commodore 64 was introduced in January 1982 at the Consumer Electronics Show in Las Vegas, which ran from January 7 to 10, 1982. Volume shipments to consumers began in August 1982 at a retail price of $595.
The core team consisted of Yash Terakura, Shiraz Shivji, Bob Russell, Bob Yannes, and David A. Ziembicki. Design work on the key chips, the VIC-II and SID, was completed in November 1981, and the full machine was ready for the January 1982 Consumer Electronics Show, with the team working through both Thanksgiving and Christmas weekends to meet the deadline.
Vertical integration was the primary factor. Commodore owned MOS Technology, its own semiconductor fabrication subsidiary, which produced the custom VIC-II graphics and SID sound chips in-house. At launch in 1982, the estimated production cost was $135 against a retail price of $595. By 1985, retail price had dropped to $149 while production costs were believed to be between $35 and $50.
The MOS Technology SID (Sound Interface Device) was a three-channel synthesizer chip with programmable ADSR envelope generators, ring modulation, and programmable filters. It was designed by Bob Yannes, who later co-founded the synthesizer company Ensoniq. BYTE magazine in July 1983 described the SID as "a true music synthesizer" and wrote that "the quality of the sound has to be heard to be believed."
Commodore announced at CeBIT in Hanover, Germany, in March 1994 that the C64 would be discontinued in 1995. However, Commodore filed for bankruptcy in April 1994, just one month later, ending all production immediately. The machine had been in production for approximately twelve years.