In Germany the threshold is around 200 Euro, more precisely up to an import VAT of 10 Euros, where the state can’t even be bothered with the paperwork. 150 for import duties, though that doesn’t apply to alcohol, tobacco and perfume, unless everything is under 45 Euros and both sender and recipient are natural persons and no money has been exchanged.

You don’t want to completely abolish thresholds as you don’t want to spend more money on collecting taxes and duties than you collect. The general strategy of the financial police seems to be to make paying duties as inconvenient for private citizens as possible, they’ll hold back the parcel and you have to go to them, probably a couple of towns over, and fetch it in person. The smart thing to do when buying from alibaba or such is to choose shipping from a EU warehouse as then all the import stuff has been dealt with by the seller.

We still do have duties within the single market, btw, because different taxes on alcohol, tobacco, etc. Relevant mostly for ølvikingar.