Over time, droop screws will indeed wear into the chassis and cause the droop setting to become difficult to set consistently, especially when one side will droop more than the other due to wear.

Many pros choose to forego the droop screws in favor of using internal shock limiters, just like we use in 1/10 racing. This keeps the setup much more consistent and is much more fool-proof.

The car I run (AE RC8.2E) has droop screws with heads on them, with the heads facing the chassis. With the larger surface area contacting the chassis, the wear factor is much, much lower.