Yes, OS/2 was dead software walking by then. That is not a big revelation: it is the central theme of this email, and it was only a year before the last ever major version of OS/2, Warp 4, released 25 September 1996.
So, yes, we know that.
What is more interesting for me is that Letwin's post misses the real point -- he mentions it, then moves on, not realising he just stated the core problem -- and that you seize upon a trivial, minor point of the message.
> rope a doped into making the world's worst character-driven graphics UI.
What?! NO!
That was TopView. That was a whole decade earlier. It was before OS/2, before Windows 1.0, before this story even started. Forget TopView.
TopView: March 1985 Windows 1.0: November 1985.
The only thing that matters about TopView is that it inspired DESQview, and that is entirely irrelevant to OS/2.
No, it's not about UI at all.
The real domino falling that killed OS/2 wasn't that OS/2 2.x ran Windows apps. That's a red herring. It's true but it was a symptom of the decline, not a cause of it.
The reason why is trivial to work out without deep knowledge of the history, so I will parenthesize it.
(OS/2 2.x didn't get native apps because it could run Windows 3.x apps.
This means: All the important stuff was on Windows.
This means: Windows was already dominant.
This means: a good version of Windows was already out when OS/2 2.x appeared.
In other words: OS/2 2.0 followed Windows 3.0.
This means: OS/2 had already lost the battle. The war was already won.
Why? Because OS/2 1.x had flopped.
Why? Because OS/2 1.x was limited to the 16-bit 80286.
So? So because OS/2 1.x flopped, Microsoft launched a product that fixed the key weakness of OS/2 1.x. That was Windows 3, which ran on 286 machines but the same binaries ALSO ran on 32-bit 80386 PCS, and used the hardware to give better multitasking of the market-dominating DOS apps than OS/2.
Win3 beat OS/2 1.x, because OS/2 1.x was crippled, so it flopped, allowing Windows to gain the upper hand.)
The really important bit of Letwin's post isn't what he thinks it is.
(And it's definitely not that footnote about text-mode UIs.)
The really important bit is not Windows apps; it's why Windows was able to gain that dominance.
It is this part:
« The miscalculation came about with the 386 coming out sooner than we expected. [...] When the 386 did come out earlier than expected and we saw what was happening, Microsoft wanted to abandon OS/2 1.0 before it was released and work on a 386-only version, one that would be able to emulate more than one DOS box and do a better job, at that. »
99% of them ran plain unaugmented PC DOS 3.3 and DOS apps, and the customers didn't give a fig about OS/2.
IBM lost a $multi-billion market through its short-sightedness, and if it had more vision, it could have couriered a 386 planar to every 286 PS/2 owner who wanted OS/2 and sent an engineer to install the board and then the OS... and still made more money overall.