For me it was in 2019 already clear that it was his last tour and I enjoyed it as much as I can. And I know with a new album a lot of people were hoping for a new tour but we have to be realistic.
But why then he would change his speech from saying goodbye to saying "I'll play no matter what"? It was such a strange move from MK. Just mid-sentence change your mind and start telling the opposite, giving people false hope, a perfectly normal way of dealing with things, nothing strange.
I think if the pandemic hadn't happened, and an opportunity had presented itself to do another tour in 2020 or 2021, he might have done it while he was still riding the wave of appreciation (I remember the love in the room after he talked about wanting to stop touring, at the Stuttgart show) and feeling in good enough shape to do it as in 2019.
With the virus and everything grinding to a halt, I think he cemented his decision.
My hypothesis is that he felt way better at the NA leg of the 2019 tour and felt he might be able to keep playing live, but the pandemic, being closed at home for so long , seeing people close to him dying, and with whatever health issues he would had, maybe was worth to keep calm at home and his desire to keep playing together with the health issues made that desire to fade out completely.
I agree.
But: This really would have been the Chance to revive Ride across the River. With all those horns
And of course: Played on a Les Paul. Missed Chance
Or what about "Planet of New Orleans". I know it was dropped from the DS tour because it was too slow or something, but it would have fit right in on the 2019 tour imo... Well, can't have everything. I'm just glad I did get to see him when it was possible.