Industry and automation made production way more cost efficient

It should still be cheaper to build a new part(, and change that part,) than a new whole(, and buy that whole).

And i.d.k. if it's the only reason for the low prices : it's cheaper for westerners to buy from non-westerners(, including mines or actions), and conversely.
Repairing is done locally(, otherwise the transport would take too long), and ends up being more expensive than buying new products made externally.
Our productivity may be higher[1], even if we're deindustrialized, but their minimum wage is way less than ours.
[1] : I.m.o., even more obviously when considering that we're in the finance sector, we may reverse things when saying that a high productivity explains the difference in living standards : it's the difference in living standards and GDP that inflates the productivity.
Since productivity∝GDP, then countries with a high GDP will have a high productivity.
And a country that increased its GDP(, e.g. through increasing its minimum wage perhaps,) would hence increase its productivity. Just an uninformed thought on my part, i.d.k. honestly.

If i keep the example of the computer mouse, it couldn't cost 20€ if it was produced locally, if only because it takes much more than 2 cumulated hours to build one, at a minimum wage of 10€/h.
Conversely though, it'd mean that it'd be very expensive for a non-westerner to buy products made in the west, which is the case, but we can still manage to sell them because we have a monopoly on new technologies(, with e.g. Japan or South Korea, but then again their minimum wage is high as well so it's the same remark), such as planes or softwares.