The motorcycle helmet part of this comment is misleading. I can walk down the street to cycle gear and buy an ECE 22.06 rated helmet with MIPS. This is because ECE is a strict superset of DOT, so companies just sell the ECE version in the US with a DOT sticker added on. (I have spoken to the helmet companies about this directly - most respond to a quick email.)

It's not like ECE vs SNELL where the standards are incompatible.