They do sell in large quantities.
Is that something you can back up with a fact or just your personal opinion? I did not find data on how many of these HWs were sold, but Ledger announced a few months ago that it had sold over 3 million devices, while some estimate that the number of Trezors is slightly less than that, but still in the millions.
I don't work at a hardware wallet company, so I have no numbers, but if you look outside the Trezor-Ledger-bubble, you'll find big communities of each of the other wallet brands (chat groups, Twitter followings, etc. - I know any one of those metrics can be faked, but look at the bigger picture).
Even though they may not sell millions, they still sell many. And I'd encourage that, instead of continuing to shill Ledger,
'it must be good because they sell many', because this shilling may be the exact reason why the others sell less than a million devices each.
I know, I know, hen and egg problem and all, but I think you get the idea.