Has fiscal devolution finally gone mainstream in UK government?

The UK's Chancellor of the Exchequer put fiscal devolution firmly on the table with her 2026 Mais Lecture, including a road map for sharing national tax revenues with English regions. Does this foreshadow a permanent shift of power, or the familiar business rate retention model in new clothing?  A model of retaining growth in tax yields without clarity on which public service responsibilities move alongside? Most importantly: what evidence and options should practitioners be assembling to feed into the Autumn Budget, including the role of inclusive growth and the risk of widening divides between mayoral strategic authorities and everywhere else?