OS/2 felt so important at first because DOS was still a gussied-up version of the rickety 16-bit software that Microsoft had licensed in 1980 for $10,000 from a tiny company called Seattle Computer Products. Windows, which first appeared in 1985, sat atop DOS and inherited its many flaws, such as the inability to utilize large amounts of memory and an eight-character limit on file names. The whole mess couldn’t utilize memory properly and was prone to frequent crashes. It was just begging to be replaced.
Of course, OS/2 never really got to do that, Microsoft doubled down on DOS and Windows took over the world.