Even though I think it was possible to buy an ONdigital box at full price without a subscription I don't think many chose to do so.
When OnDigital started, you
to buy the box, although the subscription prices were lower than for those who took out the “free whilst you subscribe” model adopted later.
When I cancelled my OnDigital subscription a few years later they told me to return the box which I refused to do, as it was mine!
Most OnDigital customers didn’t own the boxes but they also refused to return them. Freeview would’ve had a more difficult start if the boxes had been returned and TopUpTV wouldn’t have been feasible as they initially used OnDigital subscription technology.
PS I did think when I got ONdigital (later Sky) that digital standard definition TV pictures lacked the depth of the analogue pictures. And I still do feel that. I think I posted back here in mid-2006 (how long ago!) that HD reminded me of analogue.
A few years ago I connected a Freeview HD box to a 16:9 CRT using SCART and the pictures seemed very good - better, I thought, than on a modern, flatscreen TV, even though the TV could only broadcast SD.