Just as people can happily monitor through their headphones out and not buy an external interface!
Across all companies that offer sightly more affordable product ranges such as the Scarlett, they all mostly use standard components anyway.
Some do have their own components.
And something like the cans out is not likely to be made with any special components here at this price range.
Most studios have usb headphone hubs now, with extra amplification if needed.
And most people I know use a seperate amp for headphone monitoring.
They pay for themselves if your project gets to a rehearsal room stage, and you need to send the drummer a click!