Cars are much larger and their seals are much larger. They consequently have much more play and far larger tolerances.

If you scaled the forces and subjected the car to the equivalent of dropping a phone on the floor it would be totaled instantly... forget about maintaining waterproofing.

Thus I stand by my original statement: people making claims like "just a gasket and some screws" have never designed a product under similar constraints and are making bad assumptions or straight-up Dunning-Kruger errors left and right.