Beyond 30yr the people driving them are doing it for fun and aren't going to generally be running bald tires down the highway in the rain and when they do they are doing it full well knowing that they have to be super careful. Basically they know what they're getting into and don't need the state to tell them why working lights are good and brake pads shouldn't make metal noises.
Every state I have lived in requires you to register the vehicle in that state:
NC: Within 60 days of establishing a permanent residence in North Carolina, new residents who plan to operate a motor vehicle must get a North Carolina driver license and title and register their vehicles with the N.C. Division of Motor Vehicles.
GA: If you own or lease a vehicle in Georgia, you must register it with the state. [...] New residents should register their vehicle no more than 30 days from the date they move to Georgia.
Top of this thread questions whether there are mandatory safety inspections. There are in most states for most vehicles, including NC, where the author lives and where this vehicle is very likely registered. Due to the age of the vehicle, it is exempt from inspections.
You went off on a tangent saying that you don't have to register a vehicle in the state you're in. You do in NC, as well as other states I'm familiar with.
You're now suggesting ways to evade the registration requirement, which may be illegal. This is in no way a rebuttal to the registration and safety inspection requirements that were being asked about at the top of this thread. Exploiting a loophole - including potentially breaking the law - to avoid a requirement doesn’t get rid of the requirement.
https://www.ncdot.gov/dmv/title-registration/emissions-safet...
There's also an emissions inspection that varies by county, but vehicles older than 20 years are exempt.
https://www.ncdot.gov/dmv/title-registration/emissions-safet...
Does it make any sense to exempt older vehicles that are most likely to fail these inspections? No, of course it doesn't.
New vehicles within the most recent 3 model years are also exempt.