It is. Only 15 states have a periodic inspection.

https://en.m.wikipedia.org/wiki/Vehicle_inspection_in_the_United_States

Kentucky is laughable. It's literally only "inspected" if you bought the car from out of state, and the inspection was $15, and a sheriff comes out tells you to step on the brakes and turn your headlights and emergency lights on. You need 1 working headlight, any one working tail light, (yes you'll pass with just that tiny one in the center of your rear window,) and any two indicator lights to pass. The guy that did mine kicked my tires and said, "yep, it's a car."

Here in Maryland, my car, that I bought new in 1999, has technically never needed a safety inspection. Emissions every two years, but no safety. Isn't that a fun thought? If I were to sell it, it would need to be inspected then (and it's a pretty thorough inspection), but otherwise...nah.

I keep it in better condition and would never let the tires get to this point. A few months ago, I replaced a set of tires because they had aged out, and even that was longer than I usually like to keep them. But not everyone has the money or inclination (or insanity) to keep a car that old in good condition.

But, statistically, there's little evidence that safety inspections reduce crashes which kind of makes you wonder whether it's really worth it. It's one of those things that seems logical, but the statistics may not bear that out. At most, it's only a small improvement, not a drastic difference.

I haven't had an inspection in over twenty years.

We have emission checks for newly titled cars (purchase/transfer) in Georgia and Kansas. Nothing else.