Ready? Aim! Fire!!

Unfortunately Cup and cone will not last indefinitely if you want a smooth play free bearing, But if you will accept less than perfect bearings they will. Cartridge bearings are either perfect or shot and easily replaced once they are shot. Plus their lifespan is longer.

Once a cup and cone bearing system has been botched it will never be perfect again. And trying to keep it perfect always requires preventative maintenance which IMO makes it inferior to cartridge bearings. IMO cup and cone have no place on a modern mid to high end bike.