Not sure who bills it as "fighter jet to replace all fighter jets" but that's certainly not what the Operational Requirements Document for F-35 says.
It was to replace almost all of the jetfighter platforms from the A-10 to the F15 and to replace some of the bomber platforms
The F-15Cs are all pushing 40, Hornets are 30+ and because they're used by the Navy they're used hard, the A-10 is totally obsolete, and no bomber is being replaced by the F-35.