Driving on parkway car looses some power &.

The plugs had never been checked nor replaced and at 100700 miles, carbon buildup could have caused the threads to fuse together. When spark plug was removed, the fused thread resulted in the thread stripping.

You can try using a tap to rethread the hole and hope it works. Otherwise the head would have to come off for repairs. This can happen to any vehicle and during removal if the mechaninc had tried twisting in and out to loosen the spark plug to get it off instead of foecing it off directly, the damage might have been lessened.