In motorcycle helmets there was a semi scandal about 15 years ago when motorcycling magazine published a story with data that DOT level helmets provided more protection than Snell certified helmets. They lost a lot of advertising and the fallout for the reporters went on for years. A very rare instance of enthusiast press standing up, and boy did they get slapped. The DOT only helmets were superior in the magazine’s test because they were thicker foam and made a little bit less G force, as I recall. So that might be behind any rumor that a cheap bike helmet is superior to some other standard.

This all pre-dated MIPS helmets completely, iirc.

The inflatable interior helmet is not a terrible idea, it’s how some football helmets work, I think. The idea of having some kind of eggshell plastic or foam also goes back pretty far. But of course, Trek’s version changed cycling forever. We all know that because they told us so.