I'm sure you're right and I would not ride that frame no matter who said he could repair it. Anything going wrong on the front end of bike is a disaster: even a zero-speed crash (like getting a shopping bag fouled in the spokes as happened to a woman I know) throws you to the pavement so hard it can break your face off your skull and nearly kill you.

But how is that really old aluminum aircraft like DC-3s are still able to fly safely? I know they get treated really gently and lovingly by their owners but still....they've outlived most of the people who were born when they were built. Then there are the B-52Hs that are still racking up millions of flying hours on active service 50 years after the last one rolled out of Boeing's factory. Do the aluminum airframe components get replaced?