Not all the REAL gunsmiths are gone... There are just fewer of them. I understand that John Martz has not been in good health, but he is still working... just slower. The number of new gunsmiths that are not just parts changers... does seem to diminish as years go by. The reason might be that it is difficult to make a living at gunsmithing...
And then there are guys like me that still have the knowhow... but are no longer tooled to do the serious stuff... Just last year I bought a lathe, to replace the one I sold almost 20 years ago because I was moving, but I haven't had time yet to set it up properly to use it...and I haven't had access to a mill for years... Slowly I will be retooling to allow me to do things I haven't done in many years... in my "leisure" years I hope to fill my time building things I only thought about since I sold my tools... Gunsmithing isn't HARD... you just have to be careful and practice a lot before you try something on someone else's guns.