1) id Software sold to Zenimax for $150 million. [1] John Carmack was a large shareholder at the time and claimed a year ago that Zenimax still owes him another $22.5 million. Adrian Carmack owned 41% of id when he was fired & bought out of the company in 2005. From that ownership consolidation, it's very likely John had 1/3 or more of the company when it was sold to Zenimax.
2) Oculus was purchased for $2 billion. $400m in cash and 23 million shares of Facebook. Those shares would now be worth $4.2 billion. Carmack owned a position in Oculus pre the Andreessen Horowitz investment. A 1% stake would have been a substantial windfall.
3) He earned a large amount of money from being an owner of id Software from the Wolfenstein days forward.
According to Wired, he put $8m into Armadillo before closing it down. The id sale alone covers that cost at least twice over after taxes.
[1] https://arstechnica.com/tech-policy/2017/03/john-carmack-zen...
Armadillo Aerospace went into "hibernation" in 2013 and sold off its assets.