Just because Rossi doesn't have them on his M1 doesn't mean you should replace them with little chrome plates.
Now I get an eyeball full of elbow any time I glance in mine (if sitting up, I see the horizon or sky if I'm tucked in), but I can just tuck my elbow in real quick to get a glance of the cars around me. Granted I still usually do a headcheck in addition to this, because of the massive blind spots, but the mirrors are extremely helpful.
I noticed that if you multiple the square inches of polished aluminum/chrome by the number of fasteners which have been replaced by spikes, then multiply this quantity by the number of skulls or Icon stickers (and then normalize this quantity), you have a rough approximation as to the likelihood that the bike will be missing its mirrors.
On a side note, I did see one guy on a Night Rod that had his mirrors turned down. This actually seemed pretty neat and wouldn't really hurt anything.