Sounds like somebody "adjusted" the steering center aduster screw. That's a no-no! Usually wears the box out quickly, while making the car drive weird.
You'll need to check that properly (info is in the factory service manual), also check for binding steering components. I've seen unlubed ball joints cause that problem also, but that's unusual.
After testing all front end components for wear and other difficulties, have the alignment checked. Zero caster or a slight negative caster will seriously contribute to no steering return. But rarely will the alignment be set that way, and it's difficult for negative caster to just "happen" to both sides of the suspension. That's why I suggest checking the steering gearbox first.
Glenn Uettwiller
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