Yes... Who doesn't?
Why don't you go ask all the importers in this country.
Answer is hardly anyone is willing to evade tax because it is illegal.
Yes... Who doesn't?
Hardly anyone? Care to back that up? Yes, it's illegal, but illegal isn't a synonym for wrong or immoral.
I, as well as others and the OP are talking about individuals buying things for their own use, why are you talking about corporations importing products for sale?
Because it's irrelevant? The premise of the OP is that they are buying stuff from the US because they can't get it here, this is typically the number one reason people buy stuff internationally.
But yes, it does make a big difference. If the parcel gets through, great, you've avoided excessive unjust fees, nothing else happens. The worst that happens is that they realise and charge the correct amount in fees before they send it on.
If companies are found to be doing the same, it's not so good for them.