I agree completely. What I said only applies to "most" species' seeds.
"Must use fresh" and "never dry out" seeds are fairly rare, but I don't know whether that means 10%, 1% or 0.1% of species that are propagated by seed. I guess that tropical plants lean more that way?
I went looking for the right buzzwords to research this further. So far all I've found are "Recalcitrant" and "Unorthodox" seeds. And the sources that pop up tend to be about forestry.
"Today two major classes of seed are recognised (Roberts 1973):
Orthodox. Seeds which can be dried down to a low MC of around 5% (wet basis) and successfully stored at low or sub-freezing temperatures for long periods.
Recalcitrant. Seeds which cannot survive drying below a relatively high moisture content (often in the range 20–50% wet basis) and which cannot be successfully stored for long periods."
"Recalcitrant seeds include a number of large seeds that cannot withstand appreciable drying without injury; it is of interest that the overwhelming majority of recalcitrant species listed by King and Roberts (1979) are woody."
KING, M.W. and ROBERTS, E.H. (1979): The storage of recalcitrant seeds -achievements and possible approaches. International Board for Plant Genetic Resources. AGP:IBPGR/79/44 Rome.
"Most short-lived recalcitrant tropical species are constituents of the moist tropical forests, where conditions conducive to immediate germination (high humidity and high temperature) are prevalent throughout the year. Typical genera are Hevea, Swietenia, Terminalia and Triplochiton, as well as a number of Dipterocarp genera such as Dryabalanops, Dipterocarpus and Shorea and some species of Araucaria."
"Generally speaking, most tropical pioneer species have orthodox seeds but many climax species have recalcitrant or intermediate seeds."
Flores, E.M.; J. A. Vozzo Editor. "Ch 1. Seed Biology" (PDF). Tropical Tree Seed Manual. USDA Forest Service. Retrieved 2011-12-24.