One issue I see is the aging of capacitors. They tend not to do so gracefully. Inductors, when properly designed, tend to vastly outlast an electrolytic capacitor. I would imagine the cost to be less also, for a given efficiency.
Hands up all those who have replaced high ESR electrolytics in a SMPS...
Hands up all those who have replaced a shorted inductor in a SMPS...
The inductors carry...
Good thought thou, ideas are what drive industry... never know when the next one is a winner