Re: How sensible
Blame the Universal Postal Union which charges incredibly low rates for handling packages China ships to other countries as it is considered to be a "developing" country.
At one point it was less than a penny for CN to UK, hence the proliferation of ebay and amazon sellers who could charge you a pound for some random piece of tat and somehow still make money sending it to you. Not sure what it is currently as nothing seems to be publicly available -- thanks UN.
The changes to force platform operators to collect VAT reined in some of that. Not sure how Temu/Shien get away with not doing that, probably by simply ignoring the rules.
Solution is to reset postage rates to properly commercial levels and the whole house of cards will collapse.