Maybe I'm not looking hard enough, but it's a long time since I saw a power supply design including a crowbar. Is it just an idea that's just come and gone? If that is the case, any idea why? It seems like a good last-ditch protection mechanism for gear with a small overvoltage margin, which includes nearly all digital stuff.
Is there another protection mechanism against regulator failure that's applied nowadays, or it just a case of wearing the risk?