Why is billet better than iron when it comes to the gears anyways, isn't it the actual timing chain that goes ta hell ?
The thing here is that wear metals have to be compatable or you'll experience premature failure of one (or more) componants. Hence your need to keep replacing distributor gears.
You may also note that even when these metals ARE compatable, the action of one part riding, rubbing, sliding against and/or rolling across the other establishes a wear pattern on both. That wear pattern WILL effect the service life of one componant IF we replace it and not the others. In other words, it is prudent to replace your timing gears & chain as a set. And FWIW...no, it aint just the chain that wears. Gears wear too. In fact, if you install a new chain onto the old gears, the new chain will not have proper tooth contact which in turn will cause the little rollers to wear out faster than before.
Far as modern timing chains needing a steel gear goes...yes they do. Otherwise, as you have seen with your steel cam & iron distributor drive, the steel will eat-up the iron.
If I seem to be repeating myself here, it's 'cause I am. Reason is, this is important stuff to know when we set about selecting engine parts, replacing wheel bearings, power train parts, gears and stuff.
Hope this helps.