It had been clarified, when the HDMI version was released: Nov 17, 2020:
It’s possible for an HDMI Tablo to handle a lifetime subscription? They just won’t sell new ones.
Bingo.
You could always use an already purchased Lifetime subscription on an HDMI device.
Suspect most users only spend money on one Tablo, and storage. Of course many Community members have multiple devices… but we aren’t representative of typical users.
When they came out with their new Quad a couple years back they couldn’t keep them in stock long enough. Yea, if you allow firmware upgrade to legacy devices to have the same features as new ones… there’s little reason to ever buy a new one.
As for the “subscription”. I believe the data actually comes from a 3rd party - Gracenote, so there’s likely minimal profit for Nuvyyo. It does allow them some structure for a DB for the shows/series, networks and all that info for organization.