My little theory is that because Mark's dear mother has died not so long ago, he was probably struck with the nostalgia lightning so hard he decided to revisit his roots once again, but this time properly with a weekly show instead of occasional and now almost forgotten mid-90s programme. Sort of a tribute to the "Listen with Mother".
Another little and crazy idea is that Mark decided to do a weekly show so he can book extra hours in the studio to work on songs and have another additional reason to do so. As was mentioned before, family life takes a lot of your free time (kids or no kids), so it's great to have this sort of an office to do stuff. For the man who writes more on the road than at home it seems a legit theory.