I know of a few instances of folks successfully riding bikes of that caliber on long tours. … He was road touring though.
I think there’s a fundamental difference between road touring and MTB touring, though. If something breaks down on the road, it’s probably not life-threatening. The road tourist can flag down a passing car or pickup to get help, like the two people who had blowouts when we were riding. Hitch a ride into town, get the wheel fixed or a new tire, and there’s a good story to tell when you get home. If the same thing happens to a solo rider in 95F heat, 30 miles from the nearest road and water source, that’s a much more serious problem.
I think you are over reacting and the comment wasn't a "recommendation" to use a Walmart bike. This forum gets a lot of questions about using basically unsuitable bikes for specific tours, etc. and the reply that a Walmart bike could be used was meant to be facetious.
It wasn’t obvious to me that it was facetious. Note it’s from a first time poster, with no emoticons or context.
Some of the bikes at my local Wally-world look like they have brake pads of plastic mounted on stamped metal brakes. Most of the time on the TransAm we had a nice run-out at the bottom of steep hills, such that if the brakes failed you could drag to a stop with the other wheel’s brake. Now imagine heading down a 15% grade toward a cliff, and the front brake's stamped metal arm snaps. Now you have a dangerous, life threatening failure. Could it have been prevented? Sure, with “adequate preparation,” such as replacing the brakes, or inspecting them every night for cracks. Do the people who want to do things very cheaply know they need to do that?
Again, it’s just MHO, but a drive-by post saying something is possible on a forum (such as this) where people come for equipment recommendations and detailed discussions is not responsible. It’s like finding a forum for troubled teens and saying, “I’m pretty sure it’s possible to stow away in an airplane wheel well if you want to fly to Hawaii.” Even if one person did it and lived to tell the tale doesn’t mean the next one will survive.