There were any number of better operating systems at the time than DOS, especially in the 1.0 timeframe. CP/M was arguably at least on par. Any number of 16-bit minicomputer operating systems. Probably a bit early for Unix realistically.

Compared to Unix and especially modern operating systems DOS is more comparable to firmware than OS, it was something ultra minimal which basically got out of the way of developers. And being so minimal it allowed IBM PCs to sell for prices below $10,000 (1980s! dollars). This was they key to the success of Microsoft and the IBM PC. You might have created a ‘better’ OS at the time, but no one cared about your fancy slow OS which used all the memory cost a fortune in hardware.

perhaps my tendency to expression is overly ironical and indirect at the cost of clarity and obviousness, but I meant it seemed biased that Gates described the reason why MS won out over superior tech was due to 'luck'

Clearly Microsoft did lots of things right (and wrong) over the years. And one of them was creating DOS in the first place. But IBM could have presumably gone in a different direction for the IBM PC fairly easily. And had they done so, it's reasonable to speculate you might never have heard of Microsoft.

It is biased as it is coming from the winners. But it does say something that Gates was willing to admit that it was because of some glorious amazing product that they were successful.

A big part of it was also Gates ruthless business practices.