Some scrub brakes work much better than others. The one on my Alexander-Reynolds will lock the tire if you want. The one on my Gilson is almost useless.
The drum brake on my Azuza wheel is nothing to write home about, but the drum setup on my George Barris bike will lock the tire.
As far as wearing your tire goes...You are going to wear something eventually to stop whether it's a tire or a brake shoe, etc.