I used no lube on my last chain and sprocket set and it went 23,000 miles. The rear sprocket showed no visible wear and the front sprocket showed just slight wear, both still very usable, the rear I could have left on and run the new chain on. The chain I took off was still OK too but it was starting to need adjustment more often so I swapped out the set.

The theory I have on my sprockets not being worn is that with no lube on my chain no abrasive dirt sticks to my chain so they wear very little.

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!