Thanks for clearing up my misinterpretation of post #6.
I took the time to completely read the web page
Tablo TV Guide Data Subscription and I just learned that if you don't subscribe to the guide service, you still get 1 day's worth of the guide. (The subscription gets you 14 days).
A 1 day guide would be acceptable to me as long as it would still let you schedule recordings of recurring shows (e.g. the nightly news). Does it?
I have been checking the ATSC 3 Tablo status occasionally for many months and it seems to keep getting delayed longer than estimated.
.... As for Amazon's discontinuation of the Re-cast, I think it is probably related to ATSC 3. And Amazon might not have wanted to make the necessary investment to support it in the Re-cast, which would be substantial.