I would disagree. System failure modes can be quite complex. Yes you may have a good approximation of a material's Ultimate Tensile Strength through lab testing (although it isn't a single number and can be affected by a lot of variables, so it's usually designated as a range). But if your material yielded in a way that didn't account for, it could affect the loading on a different member, and trigger an issue with an entirely different part. Real world systems are more complex than your freshman year Statics assignments