High Dynamic Range Processing
We are entering an exciting and, for some, fearful era for photography. The transition from analog film to digital capture is coming to a close. As I've mentioned before, more research resources are being applied to using digital processes in ways that traditional film-based photography could not rather than simply replicating silver-halide-based resolution and processes.
One of these is developments is called High Dynamic Range processing, suddenly popularlized by its inclusion in the latest version of Photoshop. You can read several more detailed explanations of the concept elsewhere, but the short description is one photograph is created combining multiple overlapping exposures of the same scene so that it contains a much wider range of exposure values than is possible with a single image. For examples, check out the HDR pool on Flickr. (As you'll see, one drawback is that you have to take several shots of the same scene, limiting its use to landscapes mostly and some particularly postcard-esque landscapes at that.)
One of the side effects is that the color processing tends to be either over or under saturated, like early 20th century film stock.
Photoshop has become the defacto darkroom of this new era. Can a photographer today or even 10- years from now have full control over their media without a thorough understanding of Photoshop? Diane Arbus didn't process her own photographs, but that seems to be a historical oddity, though today we are living in the era of project manager as artist and many auteurs don't have much hands-on time with their own art, so perhaps this isn't all that critical.
The thing that kind of annoys me a little bit about all that digital stuff is that each little achievement - where something that is easily doable using film can now be done digitally - is hyped as if it was the second coming of the Messiah. But that's probably just me.
As for the reference to Diane Arbus I'm quite puzzled by the comment that she "didn't process her own photographs". If I remember correctly, there's a whole chapter in the book that comes with the big show that talks about how she achieved the look of her photos; and her enlarger was shown in the museum I went to.
The questions you pose is quite relevant, though, and I think one would need to rephrase it somewhat? Can a photographer (at any given time in history) produce good photos without knowing how to get there? The answer obviously is no - unless you're happy with what Martin Parr, Helmut Newton, Nan Goldin or all those other snapshooters are/were doing.
What specific advances are you referring to? I can't actually think of too many that get heralded like their the Second Coming. Most excitement these days seems to be reserved for price drops on 6-8MP DSLRs.
I could be wrong about Arbus, but in at least two articles I read about her while her retrospective was on display here in NYC the fact that she had someone else do her darkroom work was mentioned. This struck me so oddly that it really lodged my brain. I'll have to do a bit more research.
The whole history of photography has been driven by a desire to make the artistic process easier and short-circuit the training required for painting and drawing. Certainly the rest of the art world has dispensed with any pretense that skill is required to make great art (not that I agree with this). I would however say that it is possible to make a great photograph without "knowing how to get there". It's just really hard to make two.