When I say dumbed down I do not mean made so simple a monkey can use it, I mean it is simplified in design to a point that it is redundant enough that it can reliably serve the military. For example when win vista was coming out, the army was starting to roll out xp, xp was outdated then, but the military wanted something tested and reliable. Vista was a disaster at launch, many operating systems are, which is why it makes sense for the military to wait to adopt new tech.
The biggest factor in this is software compatibility.
The history of the X86 platform can be traced through several clear generations.
DOS, the original.
Windows 3X, the first GUI OS. 85% of DOS software obsolete.
Windows for Workgroups 3.11/NT 3.51. First true networkable version of Windows, made the rest of DOS obsolete, as well as 50% of 3X software.
NT4/Win2K/95, this made 95% of all previous programs obsolete.
XP, a huge jump, but made 75% of previous programs obsolete.
And it continues to this day. Now much of this obsolescence was in the Kernal, where the newer OS simply could not run the older code. Other parts were because of changes in how networking was handles, or memory. Sometimes it was in the security behind an older version which rendered security on a newer one vulnerable if continued to be used.
Back when I first got on a "Military Network", as I said it was Banyan Vines. No real security at all, simply a way to share folders so we did not have to use "Sneaker Net" to get a report or request from one area of the unit to another. Heck, we did not even have user names and passwords! Just turn on the computer and you were in. Kind of like the "password security" on a 95 machine. Even today, most do not know that if you simply hit the escape key at the prompt it will ignore the passowrd and take you right in. And yes, the code was there to actually tighten it up, but it was feared by Microsoft that home users were not ready to remember user names and passwords and that millions would lock themselves out without an easy to use back door.
That also leaves out the problem if ship A ran apple computers, ship B ran mac computers, and ship c ran ibm computers. There is no interchangability between them. Heck when I was in the national guard we still had mac plus computers from the early 90's sitting in the shed, in military grade sliding computer boxes.
And that was common in that era prior to the PowerPC fiasco. In the previous decade every other computer platform (Amiga, ST, etc) had imploded, so we were left with only X86 LIM (Lotus-Intel-Microsoft), and Macintosh. And many in Government and Industry feared giving to much power to either one or the other. And remember, this was much more then just "Apple Vs. Microsoft". The platforms each used CPUs made by different companies, so it was also Intel Vs. Motorolla. We had yet to see the rise of AMD to give Intel competition. And the dominant business application was not run by Microsoft with Office. At this time, MS office was largely a joke, only it's word processor was favored (and that ironically among the Macintosh crowd). No, the Software giant was Lotus, with Lotus 1-2-3, and their early networking applications (Lotus Notes was the e-mail system used inside most corporations in the early 1990's).
Everybody was afraid at that time that if they gave everything to one company, it could hurt them in the future (especially after watching Commodore, Atari, HP, TI, and other implode). So diversify became standard. Make multiple standards, and in the end see which one works out the best.
And in the Government like in the corporate world, the X86 was the winner. So the rest were eventually phased out.
And yes, I do remember in Okinawa in 1990 visiting a maintenance shop on Okinawa that was using an Amiga. It was the only military owned Commodore I think I ever saw.
