32-bit Operating Systems

This is probably kind of a mundane discussion question, but why does Microsoft still continue to put out 32-bit versions of its operating systems?

What was the last x86-exclusive processor used in consumer desktops? Have there been any since the Pentium 4? The only processors I can find that are even remotely recent that do not support 64-bit are older Intel Atom models, and netbooks already run heavily cut-down versions of Windows.

I've heard for years about "compatibility problems" with 64-bit OS versions, none of which that I've ever actually encountered on my own, as a long-time 64-bit user. Is there something I'm missing here that would be problematic to them putting out only a 64-bit version?

Running windows 7 Pro here on a 32-bit atom netbook that I bought new last year. The only reason netbooks ship with "starter" is because M$ wants you to pay more. The hacked-down version is not speed optimized or anything, it's just crippled. You can literally insert a code and the full version unlocks because it's already there on the HDD, it's just the same thing with the completely arbitrary restrictions turned off.

There are certainly compatibility problems, but it concerns older software/games that I'm guessing you aren't using.

Google search Legacy system or legacy applications or other similar terms (also check wikipedia) will give you the answer to this question.

From the desktop perspective there is still quite a lot of large corporations, governments, and universities are still running older DOS/Windows 16/32-bit apps that won't run on the newer Windows versions (especially in 64-bit mode). While there are various workarounds (such as terminal emulation, emulators/VM), cost/time/re-training are usually the guiding factors when considering whether or nor to upgrade, say a company's 10,000 windows 3.1 desktops to Windows 7 (or even to Windows XP).

Aside from this, there may not be any justification (other then aging of a computer system) for these institutions to replace a system with something that has like 1000 x more processing power when all that system will be doing amounts to little more than keyboard/database entry.

Compatibility and hardware problems may prove to be a bigger problem then advanatges brought by having more then 4 Gb of working memory - especially when the application is 32 bit and can not access more memory anyway.

Because people still want/need them.

Wow, its so simple, how could I have missed it

Right, I know that's kind of the obvious answer. There's hardware out there for sure for which no 64-bit drivers are produced, but that's because the hardware is no longer supported. As for software, any that simply will not run on a modern 64-bit Windows install is likely beyond its support lifetime as well.

Even back when I was running Windows XP x64, which had very little support compared to 64-bit Vista/7, I only had problems finding a compatible driver for my nForce3 motherboard's ethernet that I was using at the time, which was really old even then. Case in point, Nvidia did not bother producing a 64-bit driver for such an outdated product. If that's the kind of situation they're using as justification to build Windows 8 32-bit, I don't see the point.

So what I really mean to ask here is why continue to develop two separate Windows versions, when the only advantage to the 32-bit version is to use hardware and software so old its not even supported by its own manufacturer?

You haven't seen the software companies use for sure. They are Microsoft main income and some programs they use is from the ms-dos days. So here is the simple reason, they will scream and not upgrade if Microsoft dropped 32bit some won't even go to 7 because it would give problems.

Also now they have a Windows 7 32bit kernel already and Windows 8 will just be win7 under the hood. It's possible they will drop 32bit next time they make a new kernel. There was talk about 7 (new kernel from XP) not having 32bit maybe for windows 9 it will be true.

I don't think they actually develop two entirely separate versions. No doubt, Windows is actually written in a development language like C++ and then compiled into 32-bit and 64-bit versions. There may be sections where things need to be optimized for each version, but that doesn't mean writing a whole separate version. I'd also assume that less and less effort is made to optimize the 32-bit version.

Which is why my original answer was "because people still want/need it." As long as there is a reasonable (profitable) demand for a 32-bit version, Microsoft will continue to supply it, whether it's truly needed or not.

What amazes me the most is that it has only been recently (in the last few years) that most manufactures have started providing 64bit compatable drivers.
Back in 2003 (when I started using XP 64) all drivers had to be 64bit, now Win7 x64 allows 32bit drivers to function the driver sub system is really messed up. For example, I can print to my printer from a 32bit browser but not a 64bit browser. It's a M$ problem caused by the new driver sub-system.