looking at the wikipedia article
"The common blacksmith's anvil is made of either forged or cast steel, tool steel, or wrought iron (cast iron anvils are generally shunned, as they are too brittle for repeated use, and do not return the energy of a hammer blow like steel). "
sounds like you can make it game balancing by making cast anvils shatter after a couple uses.
I think this would be a good approach, at least once general wear and tear is implemented. A blacksmith can cast himself a poor anvil, and then use it to make a proper anvil. Or grind out a few copper goblets before the thing breaks. I can't decide wheter I think rock anvils are a good idea or not. Maybe a single-use item. And it gets even more complicated if we allow artifact rock anvils, since artifacts are generally assumed to be nigh unbreakable.
What really made me think about this was an offhand comment in the original Fallout about how "any blacksmith can make their own anvil". I suppose we could require that the blacksmith in question have a certain skill level, but it shouldn't be the kind of bottleneck it is now.
I think the biggest problem in bootstrapping yourself up from nothing should be the creation of your first pick. Mining rock with rock tools is theoretically possible, I guess, but not really feasible unless you have an infinite amount of time to spend. And because the current material system can only handle large chunks of ore, you could never ever mine for metals with one. I think real-world civilizations did it by finding ore lying on the ground. Creating wood shovels to dig dirt and stone axes to chop down trees could be possible, but unless you found a native copper boulder on the ground, a bar of metal should really be a must. Either that or wait until the goblins bring you some.
...Can ore boulders exist in the current game? Because using one to make your first pick would be kind of cool. Once it's possible to dig up a boulder to get a chunk of rock, that is. Which, I think, was in the dev notes somewhere.