[ndisn]

He notably worked at Microsoft before founding Valve.

[bombcar]

I believe he’s confirmed that his time at Microsoft both gave him the money and the desire to make Valve and Steam.

[p_l]

The desire to switch to games was, reputedly, seeing Doom outsell Windows 3.x with none of the marketing budget (with Windows having huge one).

Then not getting enough support in trying to drum up better support for gaming at Microsoft, IIRC

[bombcar]

Gabe and Carmack are probably above Amelio and below Jobs and Gates in impact on the world - but probably above them all in impact when measured on a “desired” axis - people sought out Doom in a way that even the iPhone wasn’t.