Ok, so fossils have formed in the past when living things have died, become quickly buried and their remains or cavities become mineralised.
So, do things still die? yes!
Do environments still exist where deposition can occur quickly (even if sporadically?) and bury something:
Migrating desert dunes- yes!
River floodplains- yes!
Landslides- yes!
Beaches and coastal flats- yes!
Delta slopes and delta-top marshes- yes!
(just to list a few...)
Can minerals such as calcite still become dissolved in water? yes!
Can minerals such as calcite still precipitate out of water into a cavity or around an object? Yes!
So why in the hell wouldn't large fossils form today, even if only rarely?