It really all comes down to what it costs manufacturers to submit new equipment to UL testing for approval. The time alone can push back release dates of certain products, and God forbid UL find something wrong with the design and they have to re-submit.

They do have that loophole as long as the individual parts being approved.

Right now we are dealing with a lift that nearly took off a customers' arm. No safety mechanism, whatsoever, and the emergency release switch is actually BEHIND a flush mounted panel, held with four cabinet latches! It was difficult to get to with a flat head screw driver, let alone with a hand in a panic situation.