I think DSLRs are destined for demise sadly.  Yes third gen cameras will replace them.  Briefly, I found the following reasons for such a likely transition:

a.  Both Canon and Nikon took advantage of users' commitment to DSLRs and churned out some gimmicky but awful bodies particularly in the "prosumer" segment.  They targeted photography ignorant users who crave for high megapixels.  All those bodies produce terribly noisy images.
b.  Third Gen cameras lack real-time view however, they are addressing this shortcoming real fast.
c.  These new cameras are fun to carry due to size advantage.
d.  Due to absence of mirror, it is soundless and burst rate is mind blowing.
e.  Within a couple of years time these wonders are poised to pack most of the features pros and enthusiasts crave for.
f.  They produce low noise high ISO images - a staple for low light conditions.
g.  The only exception will be the action shooters from a distance (sports and wildlife).  So, when they start producing quality telephoto lenses as well, this group will also contemplate switching seriously.

I am an enthusiast unhappy DSLR user and seriously watching the developments lately.