As a developer, I always like to stay up-to-date with OS technology. Firstly, to learn about new features and technologies, which may or may not be useful for my products. And secondly, for making sure my software is compatible with these new variations (as I argued before). As a result, I was one of the relatively few people who used Windows XP x64. And I also was one of the relatively few people who didn’t skip Vista.
Especially with Windows XP x64 I noticed there just wasn’t a lot of interest for the OS from most developers. Which in itself is a tad strange, since it was the first desktop-version of Windows that was 64-bit capable. Not many companies bothered to port their software to 64-bit at an early stage. And in later years, although there were 64-bit versions of some applications, they would not always support XP x64. Even though XP itself was still supported by the same application. And XP and XP x64 were still being supported by Microsoft.
The same with Vista: even though it is still under extended support by Microsoft, we see that some applications simply don’t bother to support it at all. I think a good example is Adobe Reader. For some reason, version XI is available for XP and Windows 7/8/8.1, but Vista is stuck at version X. However, if you manually download and install Adobe Reader XI for Windows 7, it will install and work on Vista.
Another example is Google Chrome: there is a 64-bit version now, but it will only install on Windows 7 or higher (aside from the fact that they install it in “Program Files (x86)”, but that’s another story). So, I have tried to manually get it running on a Vista x64 system, and I found that it worked just fine. Only the auto-update doesn’t work properly, because it will update back to the 32-bit version. I then tried it on a Windows XP x64 system, and somewhat to my surprise it even worked there (I was not entirely sure whether the GDI fallback path was present in the 64-bit version, since it is only for Windows 7 and higher, and the default renderer uses Direct2D/DirectWrite, which XP x64 does not support).
So, while I understand that these applications were not tested properly under these OSes, and there may be some minor issues… It is perfectly possibly to get them working 100%, and I think it is a bit sad that these OSes just don’t appear to get any attention from developers. Some OSes just don’t get a lot of love, sadly.