The future that never was

Just before the end of 1989, Microsoft made available the first pre-release version of the long promised 32-bit OS/2 2.0, which was intended to be the first mass-market 32-bit PC operating system. This was accompanied by a press release detailing the $2,600 OS/2 2.0 Software Development Kit (SDK).

Unfortunately, the December 1989 pre-release of OS/2 2.0 may not have survived to the present day. But in June 1990, Microsoft shipped the second pre-release of the OS/2 2.0 SDK. And that version has now turned up, after twenty years of searching, and nearly a quarter century after its release!
↫ Michal Necasek at OS/2 Museum

OS/2 is one of the biggest what-ifs in tech, and the whole origin story and demise of the platform is worthy of a big budget drama series. It also happens to be one of my favourite retrocomputing platforms of all time, so I may be biased.