it's the size...
the bigger your baby is, the higher the class..
BUT 1 impt thing, FZ20 has got hotshoe, makes it DSLR like. but all prosumer cam ba.. coz got aperture control, shutter control, manual control..
compare to a $700 ixus where u can only PnS, go to night mode, and the flash works for about 1 m etc... you have a clear distinction between prosumer and compact.
depends.. most money conscious prosumers probably won't understand the need for dSLRs.. it's most prob after they mix with the bad circles (aka the dark and light sides) that they see the greener grass on the other side..
but yeah, super zooms won't go out of flavour.. esp when a good leica zoom lens will cost a few times the cost price of a brand new low cost DSLR