Bill Gates wrote (mostly himself) the number one BASIC implementation, something important enough that IBM thought they had to have it - this was not luck in the same way DOS was luck. Even if the first PC shipped with CP/M as the OS instead of DOS, Gates would still have been there. Microsoft wouldn't have Windows today, but I think it is safe to say they would still have Office.
Luck is involved in getting to the top. However there is a lot of hard work required to take advantage of it. The unsuccessful often have better luck when you look close - but they don't use their luck.
Gates wrote BASIC, in an age where people scrambled to solder their own boards and connect circuitboards. Later Microsoft offered Visual Basic, including ability to design your own forms and tie-in with code and data sources.
In hindsight, we know what really worked was Windows and Office. It is a kind of luck to be so ahead of the curve, you can sort of coast, although it's a lot of hard work, somehow the right people falls in your lap as well as predatory opportunities (clone, buy and steal your competition).
While hobbyists and IBM scrambled, someone invested into the budding IBM PC-clone platform. This is business acumen fueled by superior technological vision and clarity (though at the same time blind).
Jobs had his own niche, catering more for end-UX and designers also ruthlessly, ironically.
Luck is involved in getting to the top. However there is a lot of hard work required to take advantage of it. The unsuccessful often have better luck when you look close - but they don't use their luck.