From the NASA Dryden Research Centre website:
The X-5 was tested from 1951 until 1955 at the NACA High-Speed Research Station. Built by Bell Aircraft Company, the X-5's maiden flight was June 20, 1951. The X-5 was the first aircraft capable of sweeping its wings in flight and helped our understanding of wing-sweep angles of 20, 45, and 60 degrees at subsonic and transonic speeds.
Results of the research program demonstrated that the variable-wing-sweep principle worked. With the wings fully extended the low-speed performance was improved for take-off and landing and when swept back the high speed performance was improved and drag reduced. The pilots found they could use the variable wing sweep as a tactical control to out-perform the
accompanying escort aircraft during research missions. The X-5 flight tests provided some of the design background for the
F-111 and the Navy F-14 tactical aircraft.
Also worth looking at is this
link, the last paragraph probably answers the original question: the system used worked, but it wasn't very practical, I guess later systems/mechanisms were more robust but the aerodynamic data gathered was still very useful.
As regards pivot points F14, MiG23/27,Su17 types use pivot points some way from the fuselage, the French AVG, European Tornado had pivots close in to the fuselage.
Also Grumman's Jaguar used a similar mechanism to the X5, no idea if that was why the type failed to enter service.