(post from the US is a killer ,though),
I'd comment that that situation is almost entirely a figment of sellers imaginations ?
(and is similar to UK postage)
Sure, during covid most passenger planes were idle, so postage capacity was almost nil.
But since things have returned to 'normal', many sellers are still choosing THE most expensive postage option.
Delivery in 2 or 3 days sure costs, even more so with UPS and other private carriers. Who add customs charges.
USPS still offers std or economy international post - delivery times are reasonable.
And costs a mere fraction of the expensive options. No customs fees.
Convincing sellers of this can be a challenge. !
Was chuckling about a dual seat someone in US was offering - private carrier to Oz for a mere A$997
Hmmmm !