I firmly believe that the fact will remain that for a much lower cost of entry anyone with talent can pick up a tool that, with some limitations that can be worked around, produce professional content that can work on TV or even the big screen. That pros are using these tools currently serves to reinforce that fact. If you have talent, you now have the means to produce work that can go "all the way" with the pros with a camera you buy at Best Buy. This revolution of talent won't change as newer camcorders with higher cost come into the marketplace. The extraordinary work of Nino or Philip or the kid down the street that has been shown on Vimeo (or ABC!) won't suddenly suck. No creativity will suddenly be lost.
What will happen instead is that the market will splinter. HDSLRs are not the best by any means ergonomically for video productions and those pros with sets and crews and space and money will demand a better form factor at the very least. The filmic look in a digital camera will invade all kinds of productions and new angles, levels of light, intimacy will result with less headaches. And yes, it will be awesome for pros.
The small size, the hybrid stills/video nature of HDSLRs (they are indeed fully professional for taking stills after all), and of course the cost will firmly keep such gear one foot in the pro world as well. HDSLRs will still be useful as B cameras, for fast work, for working in small/cramped locations. Photojournalists will still use them to create short video pieces to accompany their stills. Wedding photographers will still treasure having one camera that can capture pro stills and video with one unit.
Good post on DSLR Video.