it's not going to pan out because we're going to roll back to single cores?

Frankly, the vast majority of applications don't have these classes of concurrency, capacity and computational concerns and can be adequately scaled in the traditional fashion.

Exactly what type of application are you referring to? Most server software does a lot of work in parallel. Many computationally complex algorithms are parallelizable to one degree or another. Video games usually have a lot of parallelizable number crunching, analytics very often run quite slowly, UI code requires at least a couple threads of execution, on and on goes the list... it's time to adapt the idea of traditional to include more than sequential programs

I presume that most applications that most people use most of the time do not need to scale. Most websites don't need to scale, most business apps don't need to scale, and most userland applications don't need to scale. Single-core sequential programs do just fine on comparatively resource constrained hardware for "everyday" applications. with the exception of maintaining a separate thread for UI, the examples you gave are edge cases.

I am into game dev, music dsp and highly concurrent web application development... but I recognize that these are all fringe activities.

parallelization is not only about scalability, but also performance. If a task takes 20min and can be parallelized 4X, it now takes 5 minutes. There's only a certain portion of each program that is inherently sequential. We're at 2-4 cores now, soon it will be 8-16. I'm not really in a position to comment on average joe computing... but my social circle runs PCs down to a halt regularly. If I had 8 cores and all of my apps were setup to exploit it, I'd be a very very happy man and I don't think I'm in a minority. There's analytics on large databases - every enterprise does this. There's gaming - imho not a fringe activity at all. Exactly what are these day to day applications? CRUD web apps with no analytics? word processing which certainly do parallel processing of spellchecking etc? firefox? photo editing? I honestly can't think of a program worth writing that couldn't stand to use multiple threads of execution - even gedit polls files for modification.

I agree that increased parallelization of common computing tasks could increase performance, but I believe that performance is acceptable (by the consumers and management) for most applications.

Programming games is fringe programming. I believe that most PCs are used for: CRUD web apps, VB/C# apps, productivity apps, document editors, ecommerce clients, collaboration, and communication clients.

Sure, faster programs would be great! I want it as much as the next person. Sadly, I don't see it being the Next Big Thing. I hope I'm wrong! I do think that the present high-performance community is going to get nicer tooling for parallel programming, and some of that may find its way into your everyday consumer apps but that will be in forms like Grand Central Dispatch or other library adjuncts to existing platforms, and therefore not a technological leap but rather a step in the right direction.

Polling files for modification is an example of not taking advantage of platform capability, where existing performance is "good enough." Most platforms now have filesystem hooks for modification, and if you want to improve the speed of gedit you can register an event handler.