Sounds like a simple age problem. The mechanism on the inside has mostly worn to a point that it no longer retracts the latch enough.
You or someone with mechanical skills should take the set apart to determine where the ware has taken place and see if material can be welded in place to restore things.
My lockset broke at a point of insufficient material. In order to weld it I had to grind other material out of the way.
I doubt if a locksmith will be able to help you.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles