Tag axle for truck camper rigs

I'm not going to argue it is a good idea for everyone, but the claim is they have over 100,000 miles of installed experience. With that existence proof, dismissing it out of hand without more knowledge than you read in an on-line article is probably premature. Every one of the alternatives you suggest is far more expensive than this, with the exception of 19.5 which solve only a tire capacity problem. He is not the first to do it, there have been campers sold with tag axles in the past and there are or have been other vendors for pickup truck tags. As far as I know, no deaths resulted from them. Comparing to jumping off a bridge is fallacious.

I believe the concept is workable, but probably a good solution only for a narrow set of circumstances. The reliability and safety depend a lot on details which I don't have and weren't illuminated in the article.