I don't know about "needs", but the potential of future improvements in "full frame" 35mm sensors that will allow them to easily surpass medium format makes sticking with comparatively convenient DSLR's immensely lucrative. Worse comes to worse, with better sensors in the future, I will be able to carry shorter lenses, crop more aggressively, and still maintain traditional 35mm film resolution or better.
Whatever technological improvements made to smaller sensors can and will, in all likelihood, be carried over to larger DSLR sensors. Assuming that entry-level DSLR's and top-level prosumer all-in-one's remain similar in pricing (as they are today), it's an easy choice for me to give up prosumer features like smaller size, movie mode, and compact megazoom in exchange for the imaging advantages that a larger sensor confers. 35mm-sized DSLR's are still comfortable to handhold, and to me that's what matters for my portability "threshold". Given the future choice between a better-than-35mm pocketable prosumer camera or a future DSLR with a useful ISO 12800, I know which one I'm going to choose, no matter how good that 2/3 sensor becomes.