Pretending this was a political decision (vs just being what the Windows hackers decided to use their time on)...
Let's tally the arguments so far for prioritizing 64-bit Windows development.
Pro: The Ars article lists some Win64-specific security-bug mitigation features, unclear how significant these are.
Con:
The Windows PC is a declining platform, and the current 32-bit product covers all of the platform currently. There's probably a shortage open source developers working on Windows-specifics. 32-bit is much more memory-efficient. 64-bit breaks compatibility with plugins. Address space shortage will likely be covered by the tab unloading feature mentioned in the article, before it becomes an issue in practice.
Overall sounds to me like You Ain't Gonna Need It.
I would have assumed it's declining in terms of market share (driven down by tablets/Mac/Linux) but there's a surprisingly large absolute drop coming as well:
I work for several very large telcos and I have been, so far, able to avoid both .NET and Java. Last time I wrote C# code was because Microsoft (then a client) demanded we run our application on a Windows server. I wrote a proxy that sat in front of the application (which ran on a Linux machine).
>Address space shortage will likely be covered by the tab unloading feature mentioned in the article, before it becomes an issue in practice.
before? I've seen Firefox run up against the 2gb limit[1] for years.
This 4GB space is evenly divided into two parts, with 2GB dedicated for kernel usage, and 2GB left for application usage. Each application gets its own 2GB, but all applications have to share the same 2GB kernel space.
32-bit Windows (with the 2GB limit) couldn't run the 64-bit Firefox in any case, so in the context of this discussion the 32-bit build is always getting 4GB of address space.
Let's tally the arguments so far for prioritizing 64-bit Windows development.
Pro: The Ars article lists some Win64-specific security-bug mitigation features, unclear how significant these are.
Con: The Windows PC is a declining platform, and the current 32-bit product covers all of the platform currently. There's probably a shortage open source developers working on Windows-specifics. 32-bit is much more memory-efficient. 64-bit breaks compatibility with plugins. Address space shortage will likely be covered by the tab unloading feature mentioned in the article, before it becomes an issue in practice.
Overall sounds to me like You Ain't Gonna Need It.