the radio show thing at the end?

That was my thought exactly. That did not work for me at all and didn't fit with the tone of the movie.

Makes me wonder if this was the main vehicle he was going to tell the story with, shelfed it and only kept the end. It was rather abrupt..but it also likely kept the movie from running another hour.

It was excellent. Great use of creative storytelling and auteurship. Any bum could've just slapped a "the end" card on the end and rolled the credits but Scorsese is a genius who lives and breathes films, so it's not a surprise he came up with an inventive and one-of-a-kind ending to wrap of the story. The fact that he himself comes onto the camera to look the audience in the eye and explain the seriousness of the tale immediately envokes how serious this story means to him. I wish it happened more often but, considering how most moviechat users seemed to not "get it", I think more conversational "and they lived happily ever after, the end" type endings will be continued to be used.

I thought it was morphing into "The Prairie Home Companion"