That's really not even close to true in the US. You're twisting up personal and commercial.
Most implies at least more than half. Very few states have a 10K GVWR cap on a PERSONAL vehicle registration and then require Commercial registration over that. Are there some that have weird modified "commercial" registration requirements and licensing for trucks over 10K? Sure, but not "most" by a long shot.
The operator license has entirely different limits. Many states limit the operator to 26K GVWR on a (R)eguler DL.
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Commercial operations are entirely different. Register a commercial (for hire business) vehicle over 10K GVWR and you fall into Fed and CDL requirements.