It's about the same with any economically desirable rock or mineral. Go back a couple hundred years and the pickings were plenty. You could literally walk along the surface and pick up all manner of things. As time goes by the easy pickins are mined out and you have to do some serious work to get the materials. Often times the items are still there and very plentiful but the work involved to get at it simply makes no economic sense. Of course many times the items are totally mined out but that happens more with really valuable things like gold for instance. Sometimes a new location is discovered and the supply increases and the prices drop.

I kind of doubt many would be interested in researching and developing new sources for hones because it is so specialized there simply isn't enough money in it. It would be up to some small time operator to do the work in hopes of making enough money to justify the investment and the time it would require.

If you visit old locations there are usually mine dumps and you might be surprised what can be found on many dumps. Ask any rockhound.