Also, a rapier is much quicker than a shield. A rapier is also quicker than a katana, though less destructive in impact.

Rapiers are used with a technique much different than in Japan, and blade strength is not as critical. They are normally thrust weapons. When two blades meet, the impact between them is much lower than two colliding katana. In European fencing, you generally just deflect the opponent's sword. Rapiers are much cheaper and easier to replace.

Thus, rapiers do not require the quality of a katana.

By the way, katana were not indestructable. They did break often.