...I reckon if I shipped my Pagoda here now to the US, I again would not need to pay import duty or tax, since I own this car since 1999...
Well...yes, and so. Sort of.
Depending on the state you live in or where you register your car, you will indeed have taxes to pay, and some of them rather substantial depending on the value of the car.
Massachusetts has an excise tax on cars registered, which is paid annually. Connecticut taxes vehicles as personal property, and this can be substantial. In 1979, when I bought a BMW 320i for $11,600, the personal property tax in CT was going to be near $1,000. I quickly re-registered the car in my sister's name in NY specifically to avoid that tax which I couldn't afford. New York is gregarious in collecting sales taxes. When my aunt leased her SLK350 in 2015, she had legally changed her residence from NY to MA...but was in the transition process as her home in NY was prepared for sale. Mercedes-Benz financial didn't like the idea that her mail was still going to NY, and sent her a bill for the NY sales tax on the car "to be applied to the next lease payment"; it was 8.63% which was going to be upwards of $5,000. they didn't seem to care that she had a Massachusetts driver's license and legal residence there. Took a lot of phone calls on my part to convince them otherwise. There's a personal property tax on cars here in NC, but not in SC across the nearby border. That makes it a bit less costly to live in SC.
And, Classic or antique vehicles are subject to a 2.5% duty rate on import to the USA from most countries. From Canada, zero duty.