Kernel
Gates is the founder whose 1980 IBM contract — licensing rather than selling DOS — became the most consequential single business decision in the history of software. Microsoft's subsequent four-decade dominance of operating systems and productivity software paid for the largest private philanthropy in human history (Gates Foundation, $80B+ committed) and partly funded global public-health infrastructure.
Contribution
DOS as the IBM-PC default. Windows. Office. The licensing-not-selling business model. The PC-on-every-desk doctrine. The Gates Foundation's reshaping of global vaccination and malaria response. The model of the founder who becomes a senior global health bureaucrat.
Lineage
Harvard dropout; influenced by IBM's blindness to software value; competed with Apple, beat Netscape (via the Internet Explorer bundling that triggered the 2000 antitrust case), lost the search era to Google, lost the mobile era to Apple, won the cloud era with Azure under Nadella.
Civilization-scale significance
The 20th-century technology figure whose post-CEO career most explicitly redefined what a founder can be after the company. The 21st-century template for tech-philanthropy global health funding rests largely on the Gates Foundation's institutional precedent.