Microsoft made a lot of money from MS Basic back in the day, it was the standard Basic for most machines long before MS-DOS. This mattered because it effectively made software portable between machines regardless of what OS it ran on. An MS Basic program written on a Commodore machine would run fine on an Atari, a Superbrain, TRS-80, Apple II or later an MS-DOS machine. As a result Microsoft was a major player in the microcomputer software space years before MS-DOS.