Even if a handful of unusually adapted species survive, do you think they'll survive for any meaningful amount of time in the absence of any other meaningful biosphere?

And even if they do, why do you assume they (species adapted to environments entirely distinct from 99.99% of Earth) will somehow exist long enough to speciate into a robust planet's worth of species?

The species that exist today have largely survived because collectively they exist in homestasis and regulate their environment. If every tree suddenly disappeared the human race would be gone within hours. Similarly if every warm blooded animal suddenly disappeared plants would start dying in droves within a few days.