Yeah, regular parcels are not delivered to door, and most people don't want to pay the extra for door delivery. And nowadays many just redirect their parcels to a parcel box on their commute / supermarket via the Posti app/site.

Amazon.co.uk and amazon.de that you mentioned (and some other foreign sites), though, always seem to use to-door services even in Finland. The most common one has been DHL Weltpaket Premium which Posti tries to deliver once by 14:00 (sig.req), after that it goes to post office for pickup. Of course I'm never home at that time.

Amazon.fi redirects to amazon.de nowadays, BTW, which has free shipping to Finland for 39€+ orders.