It is pervasive as you have learned. You can pick virtually anything, especially electrical items, and our local costs are often +40% and far higher than the EU or US.
I have come to realise a part of it is our variable exchange rate (xrate risk factored in) and tax compliance, add shipping and local rents and wages, but no matter how one dices the difference
If it was because of tariffs protecting local manufacturing that might be one discussion, but it is not.
Unfortunately 'icons' such as Gerry Harvey complain local noncompetitiveness is because of GST and our pollies-in-business-pockets listen, but as you rightly noted, 20% VAT is included in the foreign price comparison, all are retail comparisons, and countries such as Germany (and others) also have high wages and so on, and apparently get by quite well.