747SP inaugurated very long range (New York-Jo'burg) in April,1976. Pratt/747-200B was thought unable to go so far, and/or such sectors would be load-"thin", though yield-"high". Lockheed had barely survived bankruptcy (C-5 overrun) in 1972, but chose to launch L.1011-500 in August,1976, with a variant of RR's new 747-200B engine as RB211-524B4, duly funded by UK Govt. who ordered 6 -500 for new BA.
RR upgraded that as D4, which from 1985 gave 747/RR greater range - non-stop LHR-HKG - than 747/PW/GE. That stimulated Pratt and GE to do similarly efficient long range engines: capacity excess over 747SP/L.1011-500 was "free". From 1989 747-400, from 1991 MD11 were there. So L.1011-500's long legs were without longevity.
Lockheed might have sold more, but in 1981 they chose to terminate L.1011 program. Air India and Qantas were then in negotiation on -500.
Delta took over 3 from PanAm and United, 6. LTU operated a fleet of 2 on daily Dusseldorf-Los Angeles, 22 hr.rotation, for over a decade. When they put the slower MD11 on the route a third hull was involved. Not really a "failure", though there's a theory that "stretch" does but "shrink" does not work (see DC-9/30, DC-8/60, 727-200; but cf: 720, 747SP, Fokker 70).