Spinning turbine blades are under significant mechanical stress. Individual blades are getting as tall as a 30 story buildings, but they rotate so you need to support all that weight from one end. Further, the tips are spinning at 100+MPH constantly so dust in the air is eroding the surface.
On top of this weight savings are a major goal so their designed to just barely work for a given lifespan. So, blades that where pulled from a working turbine are still really strong, they are simply more likely to fail at some unknown point in the future.
PS: Turbines from 20+ years ago are much smaller, but faced similar issues. For scale compare the turbine blade with cars in this shot and think this thing is rotating: https://www.technology.org/2018/03/23/here-is-the-worlds-lar...