The question is: where is the catch?
Why are they less popular than say Trezor or ColdCard which are more expensive, less convenient and not very beautifully designed?
For example, if you guys were choosing a new wallet now, and came to a shop where all open source hardware wallets are represented, would you purchase an inexpensive convenient beautiful "exotic" wallet? Or would you purchase one of the same wallets you used to consider, like Trezor/Coldcard/Bitbox02 ? Why?
Well, answer is clear.
Market leaders such Ledger got the monopol. They can do what they want and have a huge marketing power.
Newcomers and game changers might try to attrack customers with good price. And there is no trick. Producing a hardware wallet now is way cheaper than 10 years back.