I'm guessing that most people already using S1 TiVo have a spare (or two). I can't see any new people joining up as there's too many alternatives available now.
I'm in a similar situation as I need to make some space in the attic. I'm probably going to end up stripping them down - cachecard, turbonet, power supply, disc mounting frame, motherboard, remote control.
Also cannot see new people getting a Tivo I have multiple Tivos in various states. Don't feel competent enough to do much with them. Seems to be normal these days to sign up for a service like Netflix, Prime and others even though Tivo does the same and more. Big benefit to me with a Tivo is being able to jump through ads. Not possible on commercial channels on a stick.
Whenever I mention Tivo to any non users the eyes glaze over