If one wants the full VAT refunded, they need to do the whole export declaration paperwork and deal directly with the local customs - might be daunting, especially if you don't read/write/speak the local language. Or have the store do the same, but I think there aren't that much stores doing it.

That's why I like the Japanese system - you show your passport with the "temporary visitor" stamp in it, and you'll get your stuff text free right at the cashier. They staple the receipt to your passport, that you're supposed to hand over to the customs point at the airport, but I never had anything checked aside from a thank you. Also there seems to be no consequences if one forgets to hand over the receipt.