Sorry, I wasn't specific enough. I meant at the OS level. Do you think that Windows will abandon 32-bit before 128-bit comes around? X86_64 might be able to execute the commands, but that doesn't mean the OS has to support it, much like how 64-bit windows doesn't "support" 16-bit apps.
I guess the idea is will they disincentive making 32-bit apps now that 64-bit has taken a large foothold? I think it should, but this is talking from a software level and and not hardware.
If we were talking about X86 itself, that a completely different can of worms to be opening.
I'd conjecture that MS will kill support for 32 bit instruction sets well in advance of ever having a 128 bit processor. The math is relatively simple here.
Right now most CPUs (in dedicated PCs) out there run either x86 or x64 instruction sets. These instruction sets are shared between the cheapo work stations, servers, and high end gaming rigs. The real drag on releasing the instruction set native to x86 is legacy device support and a lack of capability in the lower end of hardware. Like it or not, Atom and previous generation gaming systems didn't have the resources to run an x64 environment.
Knowing this, cue Intel upgrading the Atom (into the Celeron) and AMD releasing the APU. Both of these developments leverage enough resources to perform acceptably, while still offering complete x64 instruction sets. The APUs are basically the driving force of current generation video game systems, while Celeron and the APU are duking it out in the smart devices market. It wouldn't therefore be unreasonable to see the end of 32 bit instructions in the next 10 years. There'd be no devices that actually require them, and the small amount of resources they free up would basically offer a free performance boost.
The introduction of 128 bit instructions is insanely unlikely in the next ten years. I make this statement for two reasons. Other people have shown the math related to adoption of new instructions, so read previous posts for their work. Finally, who actually needs that much math? Right now the largest pure computing occurs on distributed networks of CPUs. The common CPU doesn't have to deal with exceptional mathematical loads, and the people who need that computational ability have a source for it. Whenever the average person actually needs 128 bit sized computational abilities we'll see the shift toward it. For now, it doesn't make sense for one person to drive a train to work, when they could use a car to no ill affect. Having the resources to buy a train and lay track doesn't mean it's a good idea.
RISC is not included above because it barely makes sense to be using a 64 bit processor today. I've never seen a phone with more than 4 GB of RAM, and other devices using RISC architecture have even less resources. Saying that it is possible, and being ready to pay $1200 for the next phone you buy, are two different things.
Side note:
4 bit processors are functionally dead. They might still be used as cheap DACs, but they aren't common to see today outside of specific applications.
8 bit processors are hobbyist fodder. Hello learning platform, specifically the likes of Arduino.
16 bit processors are in a murky place. They are used as DACs, but because of increased price, decreased features, and an obliterated code base they aren't as common as might be conjectured.
32 bit processors are ubiquitous. Most intelligent devices running ARM are lumped in here, along with newer hobbyist hardware.
64 bit processors are ubiquitous in the PC market.
128 bit processors haven't ever been produced. There have been one off systems with one component being 128 bit, but never have we seen a true 128 bit processor.
It's funny, anyone remember Itanium? A cpu that could only run 32 bit when 16 bit was mostly predominant. Don't know why I thought of that.... but still, either cisc, or risc, 128 bit is coming....
So, who runs Itanium today?
I remember Itanium as a substantial leap forward, that landed on a rake and wound up with a huge bruise on its face. It ran 64 bit, when 32 bit was common:
http://en.wikipedia.org/wiki/Itanium
I'm betting your current system is x86-64, despite Itanium having come on the scene as pure x64 years ago.
It's also fallacious to say "it's coming," as if that were a justification for anything. You and I have an upcoming and inevitable death, which is coming. The death of our sun is coming. The extinction of our universe is coming. These things are inevitable, while 128 bit computers is not inevitable.