Most nubs don't wear down, no. Maybe you're using them differently from many other, I don't know. But if you miss your left hand nub, there have been a few suggestions here through the years. One is a dab of glue on the homing position. Never tried that one myself. The ones I've used is simply scratching the key a little (won't make a bump but it'll still be tactile enough) and carefully raising a slight ridge in the key's surface with a soldering iron (worked fine, but do not blame me if something gets borked!).

Of course, it should've been I not U under Dvorak!  ( ಸ‿ಸ)ಽ

As I got used to the Wide mod, I eventually realized that I don't feel dependent on homing nubs anymore. I just go by the geometry of the board now, I guess. Maybe I still feel that little scratch on my right hand homing key, I'm not sure.