Couldn't one of all these hardware wallet companies implement something like that and steal millions of dollars worth of BTC, in just one moment? It would probably be the worst scandal of the crypto space.
Technically could, although there would be no way to prove this as far as I'm aware, so there isn't a way to verify it either. It would be a pretty sophisticated attack though, it reminds me how computer forensics would freeze computers in the past, specifically the ram in order to extract data. Also, I do believe that some programs in the past, which I can't recall right now would give you supposedly random data, i.e a password generation based on the temperature of the device, and various other things.
I'm not sure how plausible this kind of attack would be though.
In general I would always generate my own keys and NEVER use 3rd party sw, its just too easy on linux on one command line to generate a real good key that your certain that nobody on earth knows other than you.
But, HW random number generators have better uses than generating private keys for new wallets, the best use is as seed generators for finding ( hacking ) lost bitcoins
There are 300M used bitcoin addresses, you put them into a 8gb bloom filter and on a GPU card you can do 1 billion cycles per second,, so that 8* 10**18 , so you want to make sure your seed is really random while on the hunt; now that is a use for hw random generators such as these devices
I'm fond of RNGONE from czech found on ebay and/or amazon back pre-CONVID
https://github.com/room101-dev/Grand-Ultimate-BTC-Hacker