You'll need to have strong backward compatibility with a popular system for it to have chance to become popular. MS-DOS was compatible with CP/M when it came o

You'll need to have strong backward compatibility with a popular system for it to have chance to become popular. MS-DOS was compatible with CP/M when it came out and MS kept working on backward compatibility since then. Linux was unix-like and filled a hole for a FOSS unix-like OS at the right time. The GNU utilities were among the first things that were made to work on it and it was kinda source-compatible with other unixes. If your new system requires that everything under the sun gets ported to it before people can use their favorite tools, it will fail. BTW, Gates didn't write his own OS, he bought it and got people in his company to work on it.