My understanding was that the first release of Windows came a long time after the initial announcement, but it was a little before my time.
Microsoft's usual strategy, that no one has explicitly stated yet, is to try and discourage its customers from buying a product by promising the moon 'just around the corner' for a couple years. Microsoft is seen as a better long term bet, and this depresses sales even though it doesn't actually have a product yet, creating a self-fulfilling prophecy of the failure of its competitors.
So when people are angrily referring to Microsoft vaporware, that's what they're talking about.
Microsoft's usual strategy, that no one has explicitly stated yet, is to try and discourage its customers from buying a product by promising the moon 'just around the corner' for a couple years. Microsoft is seen as a better long term bet, and this depresses sales even though it doesn't actually have a product yet, creating a self-fulfilling prophecy of the failure of its competitors.
So when people are angrily referring to Microsoft vaporware, that's what they're talking about.