Comment by wpm

Imagine you drop your laptop from a standing height onto a hard surface.

Metal will bend and deform. Dent.

Plastic will yield, then crack.

You can then replace the cracked component, because the plastic took the vast majority of the force so the metal frame on the inside that holds everything together is fine. Same way you have squishy muscle to absorb impacts that might break your bones. Same way cars have crumple zones.

I've been a Mac user primarily for 20 years. I've had or used extensively every generation of PowerBook and MacBook since the G4. I have two Thinkpads (T420, A485) and they both feel as solid as anything I've had from Apple, except when my MacBook Air slid off my couch onto its back corner, it misaligned the lid permanently, and my Thinkpads bounced.