Tucker's ratings jumped after 12/3/2019, reaching 5,359,000 average viewers in Sept/Oct 2020. So yeah, it's a ratings collapse.
All cable news ratings jumped in Sept/Oct because of the election. Then the election ended, and things went back to normal. That isn’t collapse, that is reversion to the mean. Just like when the ESPN ratings drop the day after the SuperBowl, people don’t say the ratings collapsed, they say they went back to normal.